Light emitting diode (LED) tube lamp

ABSTRACT

An LED tube lamp includes a first rectifying circuit, a second rectifying circuit, an LED lighting module, a mode determination circuit and a mode switching circuit. The first rectifying circuit is coupled to a first pin and second pin and is configured to rectify an external driving signal transmitted from the first pin and/or the second pin. The second rectifying circuit is coupled to a third pin and a fourth pin and is configured to rectify the external driving signal with the first rectifying circuit. The filter circuit is coupled to the first rectifying circuit and configured to filter the rectified signal. The LED lighting module has a driving circuit and an LED module, and is coupled to the filter circuit and is connected to receive the filtered signal. The mode determination circuit is configured to generate a first determined result signal based on the external driving signal. The mode switching circuit is coupled to the filter circuit and the driving circuit, and is configured to determine whether to perform a first driving mode or a second driving mode based on the first determined result signal. The driving circuit receives a filtered signal from the filtering circuit and drives the LED module light when performing the first driving mode, and the filtered signal bypasses at least a component of the driving circuit to drive the LED module to light when performing the second driving model.

RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patent application Ser. No. 15/055,630, filed Feb. 28, 2016, in the United States Patent and Trademark Office, the entire contents of which are incorporated herein by reference, and which claims the benefit of priority under 35 U.S.C. §119 to the following Chinese Patent Applications, filed with the State Intellectual Property Office (SIPO), the entire contents of each of which are incorporated herein by reference: CN201510104823.3, filed Mar. 10, 2015; CN201510134586.5, filed Mar. 26, 2015; CN201510133689.x, filed Mar. 25, 2015; CN201510173861.4, filed Apr. 14, 2015; CN201510193980.6, filed Apr. 22, 2015; CN201510372375.5, filed Jun. 26, 2015; CN201510284720.x, filed May 29, 2015; CN201510338027.6, filed Jun. 17, 2015; CN201510315636.x, filed Jun. 10, 2015; CN201510406595.5, filed Jul. 10, 2015; CN201510486115.0, filed Aug. 8, 2015; CN201510557717.0, filed Sep. 6, 2015; CN201510595173.7, filed Sep. 18, 2015; CN201510530110.3, filed Aug. 26, 2015; CN201510680883.X, filed Oct. 20, 2015; CN201510075925.7, filed Feb. 12, 2015; CN201510259151.3, filed May 19, 2015; CN201510324394.0, filed Jun. 12, 2015; CN201510373492.3, filed Jun. 26, 2015; CN201510482944.1, filed Aug. 7, 2015; CN201510499512.1, filed Aug. 14, 2015; CN201510448220.5, filed Jul. 27, 2015; CN201510483475.5, filed Aug. 8, 2015; CN201510555543.4, filed Sep. 2, 2015; CN201510724263.1, filed Oct. 29, 2015; and CN201610050944.9, filed Jan. 26, 2016. In addition, this application claims the benefit of priority under 35 U.S.C. §119 to the following Chinese Patent Applications: CN201510724135.7, filed Oct. 29, 2015; CN201610085895.2, filed Feb. 15, 2016; and CN201610120993.5, filed Mar. 3, 2016, the entire contents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The disclosed embodiments relate to illumination devices, and more particularly to an LED tube lamp and its components including the light sources, electronic components, and end caps.

BACKGROUND

LED lighting technology is rapidly developing to replace traditional incandescent and fluorescent lightings. LED tube lamps are mercury-free in comparison with fluorescent tube lamps that are filled with inert gas and mercury. Thus, LED tube lamps are becoming an illumination option among different available lighting systems used in homes and workplaces, which used to be dominated by traditional lighting options such as compact fluorescent light bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tube lamps include improved durability and longevity and far less energy consumption; therefore, when taking into account all factors, they are typically considered a cost effective lighting option.

Typical LED tube lamps each have a variety of LED lamp components and driving circuits. The LED lamp components include LED chip-packaging elements, light diffusion elements, high efficient heat dissipating elements, light reflective boards and light diffusing boards. Heat generated by the LED lamp components and the driving elements is considerable and mainly dominates the illumination intensity such that the heat dissipation should be properly disposed to avoid rapid decrease of the luminance and the lifetime of the LED lamps. Thus, power loss, rapid light decay, and short lifetime due to poor heat dissipation tend to be factors to be considered when improving the performance of the LED illuminating system.

Nowadays, most LED tube lamps use plastic tubes and metallic elements to dissipate heat from the LEDs. The metallic elements are usually exposed to the outside of the plastic tubes. This design improves heat dissipation but heightens the risk of electric shocks. The metallic elements may be disposed inside the plastic tubes; however, the heat still remains inside the plastic tubes and deforms the plastic tubes. Deformation of the plastic tubes may also occur when the elements to dissipate heat from the LEDs are not metallic.

The metallic elements disposed to dissipate heat from the LEDs may be made of aluminum. However, aluminum is typically too soft to sufficiently support the plastic tubes when the deformation of plastic tubes occurs due to the heat as far as the metallic elements disposed inside the plastic tubes are concerned.

The conventional LED tube lamp has a tube, a circuit board with a light source deposited in the tube lamp, and two end caps on two ends of the tube lamp. A power source is installed in the end caps and electrically connected to the light source through the circuit board. An appropriate LED driver is a direct current (DC) power source, whereas the driving signal for the florescent lamp is an alternating current (AC) signal with low frequency and low voltage or an AC signal with high frequency and high voltage. The driving signals for the florescent lamp are not DC signals and have different frequencies and voltages, so they cannot be used to drive the LED without a rectification circuit.

Current ways of using LED lamps, such as LED tube lamps, to replace traditional lighting devices (referring mainly to fluorescent lamps) include using a ballast-compatible LED tube lamp. Typically, because there is no need to change the electrical or conductive wirings in the traditional lamps, an LED tube lamp can be used to directly replace (e.g., a fluorescent lamp). Common main types of ballasts include inductive (magnetic) ballast and electronic ballast, and common electronic ballasts can include instant-start ballasts and program-start ballasts. The inductive ballast only use one single coil to provide a high voltage pulses needed to start the fluorescent lamp and limit the maximum tube current. An electronic ballast typically includes a resonant circuit and is designed to match the loading characteristics of a fluorescent lamp in driving the fluorescent lamp. For example, for properly starting a fluorescent lamp, the electronic ballast provides driving methods respectively corresponding to the fluorescent lamp working as a capacitive device before emitting light, and working as a resistive device upon emitting light. But an LED is a nonlinear component with different characteristics from a fluorescent lamp. Therefore, using an LED tube lamp with an electronic ballast impacts the resonant circuit design of the electronic ballast, which may cause a compatibility problem.

SUMMARY

The disclosed embodiments provide a light emitting diode (LED) tube lamp, and aspects thereof.

The disclosed embodiments provide an LED tube lamp, comprising a first rectifying circuit, a second rectifying circuit, an LED lighting module, a mode determination circuit and a mode switching circuit. The first rectifying circuit is coupled to a first pin and second pin and configured to rectify an external driving signal transmitted from the first pin and/or the second pin. The second rectifying circuit is coupled to a third pin and a fourth pin and is configured to rectify the external driving signal with the first rectifying circuit. The filter circuit is coupled to the first rectifying circuit and is configured to filter the rectified signal. The LED lighting module has a driving circuit and an LED module, and is coupled to the filter circuit and connected to receive the filtered signal. The mode determination circuit is configured to generate a first determined result signal based on the external driving signal. The mode switching circuit is coupled to the filter circuit and the driving circuit, and is configured to determine whether to perform a first driving mode or a second driving mode based on the first determined result signal. The driving circuit receives a filtered signal from the filtering circuit and drives the LED module light when performing the first driving mode, and the filtered signal bypasses at least a component of the driving circuit to drive the LED module to light when performing the second driving mode.

In some aspects, the mode determination circuit comprises a voltage determination circuit and generates the first determined result signal when the external driving signal is higher than a defined voltage value.

In some aspects, the voltage determination circuit comprises a symmetrical trigger diode.

In some aspects, the symmetrical trigger diode is coupled between two filtering output terminals of the filter circuit and generates the first determined result signal when the level of the filtered signal is higher than a trigger voltage of the symmetrical trigger diode.

In some aspects, the mode determination circuit further comprises a first resistor, a second resistor and a switch, the first resistor connected with the symmetrical trigger diode in series between the two filtering output terminals, the second resistor and the switch are connected in series between the two filtering output terminals, and a control of the switch is coupled to a connection node of the first resistor and the symmetrical trigger diode to generate a second determined result signal at a connection node of the second resistor and the switch.

In some aspects, the mode switching circuit has a first mode switch and a second mode switch, the first mode switch is coupled to one of a diode or a conversion switch of the driving circuit and conducts a current from/to the diode or the conversion switch based on the first determined result signal when performing the first driving mode, and the second mode switch is coupled to the filter circuit and the LED module and conducts a current from filter circuit based on the second determined result signal when performing the second driving mode.

In some aspects, the mode determination circuit comprises a frequency determination circuit and generates the first determined result signal when a frequency of the external driving signal is higher than a defined frequency value.

In some aspects, the frequency determination circuit comprises a first resistor and a capacitor connected in series.

In some aspects, the frequency determination circuit is coupled between two rectified output terminals of the rectifying circuit and generates the first determined result signal when the frequency of the rectified signal is higher than the defined frequency value.

In some aspects, the mode determination circuit further comprises a second resistor and a switch connected in series between two filtering output terminals of the filter circuit, and a control of the switch is coupled to a connection node of the first resistor and the capacitor to generate a second determined result signal at a connection node of the second resistor and the switch.

In some aspects, the mode switching circuit has a first mode switch and a second mode switch, the first mode switch is coupled to one of a diode or a conversion switch of the driving circuit and conducts a current from/to the diode or the conversion switch based on the first determined result signal when performing the first driving mode, and the second mode switch is coupled to the filter circuit and the LED module and conducts a current from filter circuit based on the second determined result signal when performing the second driving mode.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed descriptions, given by way of example, and not intended to be limiting solely thereto, will be best be understood in conjunction with the accompanying figures:

FIG. 1 is a cross-sectional view of the LED tube lamp with a light transmissive portion and a reinforcing portion in accordance with an exemplary embodiment;

FIG. 2 is a cross-sectional view of the LED tube lamp with a bracing structure in accordance with an exemplary embodiment;

FIG. 3 is a perspective view of the LED tube lamp schematically illustrating the bracing structure shown in FIG. 2;

FIG. 4 is a perspective view of the LED tube lamp with a non-circular end cap in accordance with an exemplary embodiment;

FIG. 5 is a cross-sectional view illustrating a vertical rib of the lamp tube in accordance with an exemplary embodiment;

FIG. 6 is a cross-sectional view illustrating the bracing structure of the lamp tube in accordance with an exemplary embodiment;

FIG. 7 is a cross-sectional view illustrating a ridge, which extends in an axial direction along an inner surface of the lamp tube, in accordance with an exemplary embodiment;

FIG. 8 is a cross-sectional view illustrating a compartment, which is defined by the bracing structure of the lamp tube, in accordance with an exemplary embodiment;

FIG. 9 is a cross-sectional view illustrating the bracing structure of the lamp tube in accordance with an exemplary embodiment;

FIG. 10 is a perspective view of the lamp tube shown in FIG. 9 in accordance with an exemplary embodiment;

FIG. 11 is a cross-sectional view illustrating the bracing structure of the lamp tube in accordance with an exemplary embodiment;

FIG. 12 is a cross-sectional view illustrating the LED light strip with a wiring layer in accordance with an exemplary embodiment;

FIG. 13 is a perspective view of the lamp tube shown in FIG. 12 in accordance with an exemplary embodiment;

FIG. 14 is cross-sectional view illustrating a protection layer disposed on the wiring layer in accordance with an exemplary embodiment;

FIG. 15 is a perspective view of the lamp tube shown in FIG. 14 in accordance with an exemplary embodiment;

FIG. 16 is a perspective view illustrating a dielectric layer disposed on the wiring layer adjacent to the lamp tube in accordance with an exemplary embodiment;

FIG. 17 is a perspective view of the lamp tube shown in FIG. 16 in accordance with an exemplary embodiment;

FIG. 18 is a perspective view illustrating a soldering pad on the bendable circuit sheet of the LED light strip to be joined together with the printed circuit board of the power supply in accordance with an exemplary embodiment;

FIG. 19 is a planar view illustrating an arrangement of the soldering pads on the bendable circuit sheet of the LED light strip in accordance with an exemplary embodiment;

FIG. 20 is a planar view illustrating three soldering pads in a row on the bendable circuit sheet of the LED light strip in accordance with an exemplary embodiment;

FIG. 21 is a planar view illustrating soldering pads sitting in two rows on the bendable circuit sheet of the LED light strip in accordance with an exemplary embodiment;

FIG. 22 is a planar view illustrating four soldering pads sitting in a row on the bendable circuit sheet of the LED light strip in accordance with an exemplary embodiment;

FIG. 23 is a planar view illustrating soldering pads sitting in a two by two matrix on the bendable circuit sheet of the LED light strip in accordance with an exemplary embodiment;

FIG. 24 is a planar view illustrating through holes formed on the soldering pads in accordance with an exemplary embodiment;

FIG. 25 is a cross-sectional view illustrating the soldering bonding process, which utilizes the soldering pads of the bendable circuit sheet of the LED light strip shown in FIG. 24 taken from side view and the printed circuit board of the power supply, in accordance with an exemplary embodiment;

FIG. 26 is a cross-sectional view illustrating the soldering bonding process, which utilizes the soldering pads of the bendable circuit sheet of the LED light strip shown in FIG. 24, wherein the through hole of the soldering pads is near the edge of the bendable circuit sheet, in accordance with an exemplary embodiment;

FIG. 27 is a planar view illustrating notches formed on the soldering pads in accordance with an exemplary embodiment;

FIG. 28 is a cross-sectional view of the LED light strip shown in FIG. 27 along the line A-A;

FIG. 29A is a block diagram of an exemplary power supply system for an LED tube lamp according to some embodiments;

FIG. 29B is a block diagram of an exemplary LED lamp according to some embodiments;

FIG. 29C is a block diagram of an exemplary power supply system for an LED tube lamp according to some embodiments;

FIG. 29D is a block diagram of an LED lamp according to some embodiments;

FIG. 30A is a schematic diagram of a rectifying circuit according to some embodiments;

FIG. 30B is a schematic diagram of a rectifying circuit according to some embodiments;

FIG. 31A is a block diagram of a filtering circuit according to some embodiments;

FIG. 31B is a schematic diagram of a filtering unit according to some embodiments;

FIG. 31C is a schematic diagram of a filtering unit according to some embodiments;

FIG. 31D is a schematic diagram of a filtering unit according to some embodiments;

FIG. 31E is a schematic diagram of a filtering unit according to some embodiments;

FIG. 32A is a schematic diagram of an LED module according to some embodiments;

FIG. 32B is a schematic diagram of an LED module according to some embodiments;

FIG. 32C is a plan view of a circuit layout of the LED module according to some embodiments;

FIG. 32D is a plan view of a circuit layout of the LED module according to some embodiments;

FIG. 32E is a plan view of a circuit layout of the LED module according to some embodiments;

FIG. 33A is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 33B is a block diagram of a driving circuit according to some embodiments;

FIG. 33C is a schematic diagram of a driving circuit according to some embodiments;

FIG. 33D is a schematic diagram of a driving circuit according to some embodiments;

FIG. 33E is a schematic diagram of a driving circuit according to some embodiments;

FIG. 33F is a schematic diagram of a driving circuit according to some embodiments;

FIG. 33G is a block diagram of a driving circuit according to some embodiments;

FIG. 34A is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 34B is a schematic diagram of an anti-flickering circuit according to some embodiments;

FIG. 35A is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 35B is a schematic diagram of a protection circuit according to some embodiments;

FIG. 36A is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 36B is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36C is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36D is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36E is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36F is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36G is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36H is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiments;

FIG. 36I is a schematic diagram of a mode switching circuit in an LED lamp according to some embodiment;

FIG. 36J is a schematic diagram of a mode determination circuit in an LED lamp according to some embodiment;

FIG. 36K is a schematic diagram of a mode determination circuit in an LED lamp according to some embodiment;

FIG. 37A is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 37B is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 37C is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 37D is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 37E is a schematic diagram of a ballast-compatible circuit according to some embodiments;

FIG. 37F is a schematic diagram of a ballast-compatible circuit according to some embodiments;

FIG. 37G is a block diagram of an exemplary power supply module in an LED lamp according to some embodiments;

FIG. 37H is a schematic diagram of a ballast-compatible circuit according to some embodiments;

FIG. 37I is a schematic diagram of a ballast-compatible circuit according to some embodiments;

FIG. 38A is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments;

FIG. 38B is a schematic diagram of a filament-simulating circuit according to some embodiments;

FIG. 38C is a schematic diagram of a filament-simulating circuit according to some embodiments;

FIG. 39A is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments;

FIG. 39B is a schematic diagram of an OVP circuit according to an embodiment;

FIG. 39C is a schematic diagram of an OVP circuit according to an embodiment;

FIG. 40A is a block diagram of an exemplary power supply module in an LED tube lamp according to some embodiments;

FIG. 40B is a block diagram of an installation detection module according to some embodiments;

FIG. 40C is a schematic detection pulse generating module according to some embodiments;

FIG. 40D is a schematic detection determining circuit according to some embodiments;

FIG. 40E is a schematic detection result latching circuit according to some embodiments; and

FIG. 40F is a schematic switch circuit according to some embodiments.

DETAILED DESCRIPTION

The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein. These example embodiments are just that—examples—and many implementations and variations are possible that do not require the details provided herein. It should also be emphasized that the disclosure provides details of alternative examples, but such listing of alternatives is not exhaustive. Furthermore, any consistency of detail between various examples should not be interpreted as requiring such detail—it is impracticable to list every possible variation for every feature described herein. The language of the claims should be referenced in determining the scope of the invention.

In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like numbers refer to like elements throughout. Though the different figures show variations of exemplary embodiments, these figures are not necessarily intended to be mutually exclusive from each other. Rather, as will be seen from the context of the detailed description below, certain features depicted and described in different figures can be combined with other features from other figures to result in various embodiments, when taking the figures and their description as a whole.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Also, the term “exemplary” is intended to refer to an example or illustration.

Although the figures described herein may be referred to using language such as “one embodiment,” or “certain embodiments,” these figures, and their corresponding descriptions are not intended to be mutually exclusive from other figures or descriptions, unless the context so indicates. Therefore, certain aspects from certain figures may be the same as certain features in other figures, and/or certain figures may be different representations or different portions of a particular exemplary embodiment.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. Unless the context indicates otherwise, these terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section, for example as a naming convention. Thus, a first element, component, region, layer or section discussed below in one section of the specification could be termed a second element, component, region, layer or section in another section of the specification or in the claims without departing from the teachings of the present invention. In addition, in certain cases, even if a term is not described using “first,” “second,” etc., in the specification, it may still be referred to as “first” or “second” in a claim in order to distinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that when an element is referred to as being “connected” or “coupled” to, or “on” another element, it can be directly connected or coupled to, or on the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” “in contact with,” or “directly on” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). The term “contact,” as used herein refers to a direct connection (i.e., touching) unless the context indicates otherwise.

Embodiments described herein will be described referring to plan views and/or cross-sectional views by way of ideal schematic views. Accordingly, the exemplary views may be modified depending on manufacturing technologies and/or tolerances. Therefore, the disclosed embodiments are not limited to those shown in the views, but include modifications in configuration formed on the basis of manufacturing processes. Therefore, regions exemplified in figures may have schematic properties, and shapes of regions shown in figures may exemplify specific shapes of regions of elements to which aspects of the disclosed embodiments are not limited.

Although corresponding plan views and/or perspective views of some cross-sectional view(s) may not be shown, the cross-sectional view(s) of device structures illustrated herein provide support for a plurality of device structures that extend along two different directions as would be illustrated in a plan view, and/or in three different directions as would be illustrated in a perspective view. The two different directions may or may not be orthogonal to each other. The three different directions may include a third direction that may be orthogonal to the two different directions. The plurality of device structures may be integrated in a same electronic device. For example, when a device structure (e.g., a memory cell structure or a transistor structure) is illustrated in a cross-sectional view, an electronic device may include a plurality of the device structures (e.g., memory cell structures or transistor structures), as would be illustrated by a plan view of the electronic device. The plurality of device structures may be arranged in an array and/or in a two-dimensional pattern.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element's or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Terms such as “same,” “planar,” or “coplanar,” as used herein when referring to orientation, layout, location, shapes, sizes, amounts, or other measures do not necessarily mean an exactly identical orientation, layout, location, shape, size, amount, or other measure, but are intended to encompass nearly identical orientation, layout, location, shapes, sizes, amounts, or other measures within acceptable variations that may occur, for example, due to manufacturing processes. The term “substantially” may be used herein to reflect this meaning.

As used herein, items described as being “electrically connected” are configured such that an electrical signal can be passed from one item to the other. Therefore, a passive electrically conductive component (e.g., a wire, pad, internal electrical line, etc.) physically connected to a passive electrically insulative component (e.g., a prepreg layer of a printed circuit board, an electrically insulative adhesive connecting two device, an electrically insulative underfill or mold layer, etc.) is not electrically connected to that component. Moreover, items that are “directly electrically connected,” to each other are electrically connected through one or more passive elements, such as, for example, wires, pads, internal electrical lines, through vias, etc. As such, directly electrically connected components do not include components electrically connected through active elements, such as transistors or diodes.

Components described as thermally connected or in thermal communication are arranged such that heat will follow a path between the components to allow the heat to transfer from the first component to the second component. Simply because two components are part of the same device or package does not make them thermally connected. In general, components which are heat-conductive and directly connected to other heat-conductive or heat-generating components (or connected to those components through intermediate heat-conductive components or in such close proximity as to permit a substantial transfer of heat) will be described as thermally connected to those components, or in thermal communication with those components. On the contrary, two components with heat-insulative materials therebetween, which materials significantly prevent heat transfer between the two components, or only allow for incidental heat transfer, are not described as thermally connected or in thermal communication with each other. The terms “heat-conductive” or “thermally-conductive” do not apply to a particular material simply because it provides incidental heat conduction, but are intended to refer to materials that are typically known as good heat conductors or known to have utility for transferring heat, or components having similar heat conducting properties as those materials.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In addition, unless the context indicates otherwise, steps described in a particular order need not occur in that order.

The present disclosure provides an LED tube lamp. The present disclosure will now be described in the following embodiments with reference to the drawings.

Terms such as “about” or “approximately” may reflect sizes, orientations, or layouts that vary only in a small relative manner, and/or in a way that does not significantly alter the operation, functionality, or structure of certain elements. For example, a range from “about 0.1 to about 1” may encompass a range such as a 0%-5% deviation around 0.1 and a 0% to 5% deviation around 1, especially if such deviation maintains the same effect as the listed range.

Referring to FIG. 1, in accordance with an exemplary embodiment, the light emitting diode (LED) tube lamp comprises a lamp tube 1 and an LED light assembly. The lamp tube 1 includes a light transmissive portion 105 and a reinforcing portion 107. The reinforcing portion 107 is fixedly connected to the light transmissive portion 105.

The LED light assembly is disposed inside the lamp tube 1 and includes an LED light source 202 and an LED light strip 2. The LED light source is thermally and electrically connected to the LED light strip 2, which is in turn thermally connected to the reinforcing portion 107. Heat generated by the LED light source 202 is first transmitted to the LED light strip 2 and then to the reinforcing portion 107 before egressing the lamp tube 1. Thermal connection is achieved with thermally conductive tapes or conventional mechanical fasteners such as screws aided by thermal grease to eliminate air gaps from interface areas.

Typically, the lamp tube 1 has a shape of an elongated cylinder, which is a straight structure. However, the lamp tube 1 can take any curved structure such as a ring or a horseshoe. The cross section of the lamp tube 1 defines, typically, a circle, or not as typically, an ellipse or a polygon. Alternatively, the cross section of the lamp tube 1 takes an irregular shape depending on the shapes of, respectively, the light transmissive portion 105 and the reinforcing portion 107 and on the manner the two portions interconnect to form the lamp tube 1.

The lamp tube 1 is a glass tube, a plastic tube or a tube made of any other suitable material or combination of materials. A plastic lamp tube is made from light transmissive plastic, thermally conductive plastic or a combination of both. The light transmissive plastic is one of translucent polymer matrices such as polymethyl methacrylate, polycarbonate, polystyrene, poly(styrene-co-methyl methacrylate) and a mixture thereof. Optionally, the strength and elasticity of thermally conductive plastic is enhanced by bonding a plastic matrix with glass fibers. When a lamp tube employs a combination of light transmissive plastic and thermally conductive plastic, does in the combination. In an embodiment, an outer shell of lamp tube includes a plurality of layers made from distinct materials. For example, the lamp tube includes a plastic tube coaxially sheathed by a glass tube.

In an embodiment, the light transmissive portion 105 is made from light transmissive plastic. The reinforcing portion is 107 made from thermally conductive plastic. Injection molding is used for producing the light transmissive portion 105 in a first piece and for producing the reinforcing portion 107 in a separate second piece. The first piece and the second piece are configured to be clipped together, buckled together, glued together or otherwise fixedly interconnect to form the lamp tube 1. Alternatively, injection molding is used for producing the lamp tube 1, which includes the light transmissive portion 105 and the reinforcing portion 107, in an integral piece by feeding two types of plastic materials into a molding process. In an alternative embodiment, the reinforcing portion is made of metal having good thermal conductivity such as aluminum alloy and copper alloy.

Respective shapes of the light transmissive portion 105 and the reinforcing portion 107, how the two portions 105, 107 interconnect to form the lamp tube 1 and the respective proportions of the two portions 105, 107 in the lamp tube depend on one or more considerations, such as, for example, field angle, heat dissipation efficiency and structural strength. A wider field angle—potentially at the expense of heat dissipation capability and structural strength—is achieved when the proportion of the light transmissive portion increases 105 in relation to that of the reinforcing portion 107. By contrast, the lamp tube benefits from an increased proportion of the reinforcing portion 107 in relation to that of the light transmissive portion in such ways as better heat dissipation and rigidity but potentially loses field angle.

In some embodiments, the reinforcing portion 107 includes a plurality of protruding parts. In other embodiments, a plurality of protruding parts are disposed on the surface of the LED light strip 2 that is not covered by the LED light assembly. Like fins on a heatsink, the protruding part boosts heat dissipation by increasing the surface area of the reinforcing portion 107 and the LED light strip 2. The protruding parts are disposed equidistantly, or alternatively, not equidistantly.

Staying on FIG. 1, the lamp tube 1 has a shape of a circular cylinder. For example, a cross section of the lamp tube 1 defines a circle. A line H-H cuts the circle horizontally into two equal halves along a diameter of the circle. A cross section of the light transmissive portion 105 defines an upper segment on the circle. A cross section of the reinforcing portion 107 defines a lower segment on the circle. A dividing line 104 parallel to the line H-H is shared by the two segments. In the embodiment, the dividing line 104 sits exactly on the line H-H. Consequently, the area of the upper segment is the same as that of the lower segment. The cross section of the light transmissive portion 105 has a same area as that of the reinforcing portion 107.

In an alternative embodiment, the dividing line 104 is spaced apart from the line H-H. For example, when the dividing line 104 is below the line H-H, the upper segment, which encompasses the light transmissive portion, has a greater area than the lower segment, which encompasses the reinforcing portion. The lamp tube, which includes an enlarged light transmissive portion, is thus configured to achieve a field angle wider than 180 degrees; however, other things equal, the lamp tube surrenders some heat dissipation capability, structural strength or both due to a diminished reinforcing portion 107. By contrast, the lamp tube 1 has an enlarged reinforcing portion 107 and a diminished light transmissive portion 105 if the dividing line rises above the line H-H. Other things equal, the lamp tube 1, now having an enlarged reinforcing portion 107, is configured to exhibit higher heat dissipation capability, structural strength or both; however, the field angle of the lamp tube 1 will dwindle due to diminished dimensions of the light transmissive portion 105.

The LED tube lamp is configured to convert bright spots coming from the LED light source into an evenly distributed luminous output. In an embodiment, a light diffusion layer is disposed on an inner surface of the lamp tube 1 or an outer surface of the lamp tube 1. In another embodiment, a diffusion laminate is disposed over the LED light source 202. In yet another embodiment, the lamp tube 1 has a glossy outer surface and a frosted inner surface. The inner surface is rougher than the outer surface. The roughness Ra of the inner surface may be, for example, from 0.1 to 40 μm. In some embodiments, roughness Ra of the inner surface may be from 1 to 20 μm. Controlled roughness of the surface is obtained mechanically by a cutter grinding against a workpiece, deformation on a surface of a workpiece being cut off or high frequency vibration in the manufacturing system. Alternatively, roughness is obtained chemically by etching a surface. Depending on the luminous effect the lamp tube 1 is designed to produce, a suitable combination of amplitude and frequency of a roughened surface is provided by a matching combination of workpiece and finishing technique.

In alternative embodiment, the diffusion layer is in form of an optical diffusion coating, which is composed of any one of calcium carbonate, halogen calcium phosphate and aluminum oxide, or any combination thereof. When the optical diffusion coating is made from a calcium carbonate with suitable solution, an excellent light diffusion effect and transmittance to exceed 90% can be obtained.

In alternative embodiments, the diffusion layer is in form of an optical diffusion coating, which is composed of any one of calcium carbonate, halogen calcium phosphate and aluminum oxide, or any combination thereof. When the optical diffusion coating is made from a calcium carbonate with suitable solution, an excellent light diffusion effect and transmittance to exceed 90% can be obtained.

In one embodiment, the composition of the diffusion layer in form of the optical diffusion coating includes calcium carbonate, strontium phosphate (e.g., CMS-5000, white powder), thickener, and a ceramic activated carbon (e.g., ceramic activated carbon SW-C, which is a colorless liquid). Specifically, such an optical diffusion coating on the inner circumferential surface of the glass tube has an average thickness ranging between about 20 to about 30 μm. A light transmittance of the diffusion layer using this optical diffusion coating is about 90%. Generally speaking, the light transmittance of the diffusion layer ranges from 85% to 96%. In addition, this diffusion layer can also provide electrical isolation for reducing risk of electric shock to a user upon breakage of the lamp tube 1. Furthermore, the diffusion layer provides an improved illumination distribution uniformity of the light outputted by the LED light sources 202 such that the light can illuminate the back of the light sources 202 and the side edges of the bendable circuit sheet so as to avoid the formation of dark regions inside the lamp tube 1 and improve the illumination comfort. In another possible embodiment, the light transmittance of the diffusion layer can be 92% to 94% while the thickness ranges from about 200 to about 300 μm.

In another embodiment, the optical diffusion coating can also be made of a mixture including calcium carbonate-based substance, some reflective substances like strontium phosphate or barium sulfate, a thickening agent, ceramic activated carbon, and deionized water. The mixture is coated on the inner circumferential surface of the glass tube and has an average thickness ranging between about 20 to about 30 μm. In view of the diffusion phenomena in microscopic terms, light is reflected by particles. The particle size of the reflective substance such as strontium phosphate or barium sulfate will be much larger than the particle size of the calcium carbonate. Therefore, adding a small amount of reflective substance in the optical diffusion coating can effectively increase the diffusion effect of light.

In other embodiments, halogen calcium phosphate or aluminum oxide can also serve as the main material for forming the diffusion layer. The particle size of the calcium carbonate is about 2 to 4 μm, while the particle size of the halogen calcium phosphate and aluminum oxide are about 4 to 6 μm and 1 to 2 μm, respectively. When the light transmittance is desired to be 85% to 92%, the average thickness for the optical diffusion coating mainly having the calcium carbonate is about 20 to about 30 μm, while the average thickness for the optical diffusion coating mainly having the halogen calcium phosphate may be about 25 to about 35 μm, and the average thickness for the optical diffusion coating mainly having the aluminum oxide may be about 10 to about 15 μm. However, when the desired light transmittance is up to 92% and higher, the optical diffusion coating mainly having the calcium carbonate, the halogen calcium phosphate, or the aluminum oxide is thinner.

The main material and the corresponding thickness of the optical diffusion coating can be decided according to the place for which the lamp tube 1 is used and the desired light transmittance. In some embodiments, the higher the desired light transmittance of the diffusion layer, the more apparent the grainy visual appearance of the light sources is.

In an embodiment, the LED tube lamp is configured to reduce internal reflectance by applying a layer of anti-reflection coating to an inner surface of the lamp tube 1. The coating has an upper boundary, which divides the inner surface of the lamp tube and the anti-reflection coating, and a lower boundary, which divides the anti-reflection coating and the air in the lamp tube 1. Light waves reflected by the upper and lower boundaries of the coating interfere with one another to reduce reflectance. The coating is made from a material with a refractive index of a square root of the refractive index of the light transmissive portion 105 of the lamp tube 1 by vacuum deposition. Tolerance of the coating's refractive index is ±20%. The thickness of the coating is chosen to produce destructive interference in the light reflected from the interfaces and constructive interference in the corresponding transmitted light. In an additional embodiment, reflectance is further reduced by using alternating layers of a low-index coating and a higher-index coating. The multi-layer structure is designed to, when setting parameters such as combination and permutation of layers, thickness of a layer, refractive index of the material, give low reflectivity over a broad band that covers at least 60%, or in some embodiments, 80% of the wavelength range beaming from the LED light source 202. In some embodiments, three successive layers of anti-reflection coatings are applied to an inner surface of the lamp tube 1 to obtain low reflectivity over a wide range of frequencies. The thicknesses of the coatings are chosen to give the coatings optical depths of, respectively, one half, one quarter and one half of the wavelength range coming from the LED light source 202. Dimensional tolerance for the thickness of the coating is set at ±20%.

Turning to FIG. 2, in accordance with an exemplary embodiment, the cross section of the lamp tube 1, unlike that of the cylindrical lamp tube 1 in FIG. 1, approximates an arc sitting on a flange of an I-beam. The lamp tube 1 includes a light transmissive portion 105 and a reinforcing portion 107. A cross section of the light transmissive portion 105 defines an upper segment on a circle. A line H-H cuts the circle horizontally into two equal halves along a diameter of the circle. The reinforcing portion 107 includes a platform 107 a and a bracing structure 107 b. The platform 107 a has an upper surface and a lower surface. The LED light assembly is disposed on the upper surface of the platform 107 a. The bracing structure 107 b is fixedly connected to the platform 107 a and holds the platform 107 a in place. The bracing structure 107 b includes a horizontal rib, a vertical rib, a curvilinear rib or a combination of ribs selected from the above. The dimensions of the platform 107 a, the horizontal rib and the vertical rib, their quantities and the manner they interconnect depend on one or more considerations, such as, for example, field angle, heat dissipation efficiency and structural strength. In the embodiment, the cross section of the reinforcing portion 107 approximates that of an I-beam. The platform 107 a, the vertical rib and the horizontal rib correspond to, respectively, the upper flange, the web and the bottom flange of the I-beam. In some embodiments, the bracing structure 107 b may include only one vertical rib and only one horizontal rib, though in other embodiments more than one vertical rib and/or horizontal rib may be used.

A dividing line 104 parallel to the line H-H is shared by the upper segment and the upper flange. In the embodiment, the dividing line sits below the line H-H. Consequently, the upper segment constitutes the majority of the circle. The light transmissive portion 105 may be configured to generate a field angle wider than 180 degrees. In an alternative embodiment, the dividing line sits on or above the line H-H. For example, when the dividing line rises above the line H-H, the upper segment, which encompasses the light transmissive portion, now constitutes less than half of the circle. The lamp tube 1, which has an enlarged reinforcing portion 107, may be configured for better heat dissipation and structural strength; however, other things equal, the lamp tube 1 loses some luminous filed due to a diminished light transmissive portion 105.

In an embodiment, a surface on which the LED light assembly sits—e.g. the upper surface of the platform—is configured to further reflect the light reflected from the inner surface of the lamp tube 1. The surface on which the LED light assembly sits is coated with a reflective layer. Alternatively, the surface on which the LED light assembly sits may be finished to exhibit a reflectance of 80 to 95%. In some embodiments, the surface on which the LED light assembly sits may be finished to exhibit a reflectance of 85 to 90%. Finishing is performed mechanically, chemically or by fluid jet. Mechanical finishing buffs a surface by removing peaks from the surface with an abrasive stick, a wool polishing wheel or sandpaper. A surface treated this way has a roughness Ra as low as 0.008 to 1 μm. Chemical finishing works by dissolving peaks of a surface faster than troughs of the surface with a chemical agent. Fluid jet finishing uses a high-speed stream of slurry to accurately remove nanometers of material from a surface. The slurry is prepared by adding particles such as silicon carbide powder to a fluid capable of being pumped under relatively low pressure.

Turning to FIG. 3, in accordance with an exemplary embodiment, the LED tube lamp further comprises an end cap 3, which is fixedly connected to an end of the lamp tube 1. The end cap 3 is made from plastic, metal or a combination of both. The end cap 3 and the lamp tube 1 are latched together, buckled together or otherwise mechanically fastened to one another. Alternatively, the two parts are glued together with hot-melt adhesive, e.g. a silicone matrix with a thermal conductivity of at least 0.7 Wm-1K-1.

Typically, the end cap 3 has a shape of a cylinder, and the cross section of the end cap 3 may define a circle. Alternatively, the cross section of the end cap 3 takes an irregular shape depending on the shapes of, respectively, the light transmissive portion and the reinforcing portion and on the manner the two portions and the end cap 3 interconnect to form the LED tube lamp. Regardless of the shape of the end cap 3, in some embodiments, the cross section of the end cap 3 encloses all or only a part of the cross section of the reinforcing portion 107 of the lamp tube 1. In the embodiment shown in FIG. 3, the end cap 3 defines a circular cylinder whose cross section encloses, entirely, the cross sections of, respectively, the light transmissive portion 105 and the reinforcing portion 107. The cross section of the lamp tube 1 approximates a segment, defined by the light transmissive portion 105, sitting on an upper flange of an I-beam, defined by the reinforcing portion 107. A cross section of an inner surface of the end cap 3 defines a circle. The circle shares a same arc of the segment defined by an outer surface of the light transmissive portion 105. The I-beam is enclosed, entirely, by the circle.

In an alternative embodiment shown in FIG. 4, the cross section of the end cap 3 encloses all of the cross section of the light transmissive portion 105 but only a part of that of the reinforcing portion 107. A cross section of the inner surface of the end cap 3 defines a same segment defined by an outer surface of the light transmissive portion 105. However, only the upper flange of the I-beam is enclosed by the segment, but the lower flange and the web are not.

In some embodiments, an end of the LED light assembly extends to the end cap 3 as shown in FIGS. 3 and 4. In other embodiments, an end of the LED light assembly recedes from the end cap 3.

The bracing structure 107 b may be made of metal or plastic. The metal may be pure metal, metal alloy or combination of pure metal and metal alloy with different stiffness. Similarly, the plastic may include materials with various levels of stiffness. Specifically, the plastic lamp tube 1 may include only one bracing structure with one stiffness or two bracing structures each with a different stiffness.

When only one bracing structure is adopted, the material of the only one bracing structure may be metal, metal alloy, or plastic, and the ratio of the cross-sectional area of the bracing structure to the cross-sectional area of the lamp tube 1 may be from 1:3 to 1:30. In some exemplary embodiments, the ratio of the cross-sectional area of the bracing structure to the cross-sectional area of the lamp tube 1 may be from 1:5 to 1:10.

When more than one bracing structures with different stiffness are adopted, each of the bracing structures may be made of metal, metal alloy, or plastic. In one embodiment, when two bracing structures with different stiffness are adopted, the ratio of the cross-sectional area of the bracing structure with larger stiffness to the cross-sectional area of the other bracing structure is from 0.001:1 to 100:1, and the ratio of the cross-sectional area of the bracing structure with larger stiffness to the cross-sectional area of the lamp tube 1 is from 1:20 to 1:300.

In view of the bracing structure made of metal, the cross-section of the lamp tube 1 vertically cut by a plane shows that the plane may include the following: (1) a lamp tube made of plastic, a first bracing structure made of a metal with a first stiffness, and a second bracing structure, such as a maintaining stick, made of a metal with a second stiffness different from the first stiffness; (2) a lamp tube made of plastic and a single bracing structure made of metal and/or metal alloy; or (3) a lamp tube made of plastic, a first bracing structure made of metal, and a second bracing structure, such as a maintaining stick, made of metal alloy. Similarly, various plastics with different stiffness may be used to serve as the bracing structures mentioned above according to embodiments. As long as the materials for the used bracing structures have different stiffness, the materials are not limited. For example, metal or metal alloy and plastic could serve as materials for different bracing structures without departing from the spirit of the disclosed embodiments. Additionally, the bracing structure may be made from a material having a greater stiffness than the material from which the lamp tube is made.

In some embodiments, the lamp tube includes a first end cap fixedly connecting to a first end of the lamp tube and a second end cap fixedly connecting to a second end of the lamp tube. The first end cap is dimensionally larger—e.g. from 20% to 70% larger—than the second end cap.

Shifting to FIG. 5, in accordance with an exemplary embodiment, the cross section of the lamp tube 1 approximates an arc sitting on a flange of a T-beam. The cross section of the reinforcing portion 107 approximates that of the T-beam. The platform 107 a and the vertical rib correspond to, respectively, the flange and the web of the T-beam. For instance, in some embodiments, the bracing structure 107 b may include only one vertical rib but no horizontal rib. When the cross section of the end cap 3 encloses, entirely, the cross sections of, respectively, the light transmissive portion 105 and the reinforcing portion 107, other things equal, the vertical rib in a T-beam structure (FIG. 5) has a greater length than the vertical rib in an I-beam structure (FIG. 3).

Turning to FIG. 6, in accordance with an exemplary embodiment, the bracing structure 107 b includes a vertical rib and a curvilinear rib but no horizontal rib. The cross section of the lamp tube 1 defines a circle. A cross section of the light transmissive portion 105 defines an upper arc on the circle. A cross section of the curvilinear rib defines a lower arc on the circle. A cross section of the platform 107 a and the vertical rib approximates that of a T-beam. All three ends of the T-beam sit on the lower arc. The ratio of the length of the vertical rib to the diameter of the lamp tube 1 depends on one or more considerations, such as, for example, field angle, heatsinking efficiency and structural strength. The ratio of the length of the vertical rib to the diameter of the lamp tube 1 may be, for example, from 1:1.2 to 1:30. In some embodiments, the ratio of the length of the vertical rib to the diameter of the lamp tube 1 may be from 1:3 to 1:10.

Turing to FIG. 7, in accordance with an exemplary embodiment, the lamp tube 1 further includes a ridge 235. The ridge 235 extends in an axial direction along an inner surface of the lamp tube 1. The ridge 235 is an elongated hollow structure unbroken from end to end, or alternatively, broken at intervals. Injection molding is used for producing the reinforcing portion 230 and the ridge 235 in an integral piece. The position of the ridge 235 in relation to the line H-H bisecting the circle defined by the lamp tube 1 depends on, as elaborated earlier, one or more considerations such as field angle, heatsink efficiency and structural strength.

In an embodiment, the lamp tube 1 further includes a ridge 235 and a maintaining stick 2351. The maintaining stick 2351 is, likewise, an elongated structure, which is unbroken from end to end, or alternatively, broken at intervals, and which fills up the space inside the ridge 235. The maintaining stick 2351 is made of thermally conductive plastic, or alternatively, metal. The metal is one of carbon steel, cast steel, nickel chrome steel, alloyed steel, ductile iron, grey cast iron, white cast iron, rolled manganese bronze, rolled phosphor bronze, cold-drawn bronze, rolled zinc, aluminum alloy and copper alloy. The material from which the maintaining stick 2351 is made is chosen to provide the LED tube lamp with a combination of heat dissipation capability and structural strength that is otherwise absent from other parts of the lamp tube 1. In an embodiment, the maintaining stick 2351 is made from a different material than the material from which the LED light strip 2 or the reinforcing portion 107 is made. For example, when the LED light strip 2 or the reinforcing portion 107 of the lamp tube 1 is made from a metal having superior heat dissipation capability but insufficient stiffness, e.g. aluminum panel, the maintaining stick 2351 is made from a metal stiffer than aluminum to supply more structural strength. In some embodiments, the ratio of the volume of heatsinking-oriented metal to the volume of stiffness-oriented metal in a lamp tube 1 is from 0.001:1 to 100:1, or in certain embodiments, from 0.1:1 to 10:1. In some embodiments, the ratio of the cross sectional area of the maintaining stick 2351 to that of the lamp tube 1 is from 1:20 to 1:100, or in certain embodiments, from 1:50 to 1:100.

In some embodiments, the lamp tube 1 includes a light transmissive portion and a reinforcing portion. In other embodiments, a ridge is substituted for the reinforcing portion. In some exemplary embodiments, the lamp tube 1 may include a light transmissive portion and a ridge, but no reinforcing portion. In another embodiment, the lamp tube 1 further includes a maintaining stick that fills up the space inside the ridge.

The outer surface of the reinforcing portion forms an outer surface of the lamp tube 1, as the embodiments in FIGS. 1-6. Alternatively, the outer surface of the reinforcing portion forms none of the outer surface of the lamp tube, as the embodiments in FIGS. 7-11. Where the reinforcing portion 107 is disposed entirely inside the lamp tube 1, the reinforcing portion 107 rests on the inner surface of the lamp tube 1 along a substantially uninterrupted interface, as the embodiment in FIG. 8; or alternatively, along an interrupted interface, as the embodiments in FIGS. 7, 9-11.

Focusing on FIG. 7, in accordance with an exemplary embodiment, a first compartment is defined by the reinforcing portion 107 and the inner surface of the lamp tube 1. A second compartment is defined by the LED light strip 2 and the inner surface of the lamp tube 1. Likewise, in FIG. 8, a compartment is defined by the platform 231, the horizontal rib and the curvilinear rib. In some embodiments, a ridge is disposed inside the compartment for great structural strength. In other embodiments, a maintaining stick fills up the space inside the hollow structure of the ridge.

The length of the reinforcing portion, on which the LED light assembly is disposed, in the vertical direction in relation to the diameter of the lamp tube depends on the field angle the lamp tube is designed to produce. In the embodiment shown in FIG. 7, the ratio of the distance (D) between the LED light assembly and the dome of the lamp tube 1 to the diameter of the lamp tube 1 may be, for example, from 0.25 to 0.9. In some exemplary embodiments, the ratio of the distance (D) between the LED light assembly and the dome of the lamp tube 1 to the diameter of the lamp tube 1 may be from 0.33 to 0.75.

Turning to FIG. 8, in accordance with an exemplary embodiment, the lamp tube further includes a pair of protruding bars 236. The protruding bar 236 extends in an axial direction along an inner surface of the lamp tube 1 and is configured to form a guiding channel inside the lamp tube 1. The reinforcing portion 107 is connected to the lamp tube 1 by sliding the reinforcing portion 107 into the guiding channel. In the embodiment, a cross section of an inner surface of the lamp tube 1 defines a circle. A cross section of the curvilinear rib 230 defines a lower arc on the circle. A cross section of the platform 231 and the vertical rib 233 approximates that of a T-beam. All three ends of the T-beam sit on the lower arc. The pair of protruding bars 236 and the inner surface of the lamp tube 1 form the guiding channel in the lamp tube 1. The cross section of the guiding channel is defined by the flange of the T-beam and the lower arc. The reinforcing portion 107 may be configured to fit snugly into the guiding channel.

Turning to FIGS. 9 and 10, in accordance with an exemplary embodiment, the reinforcing portion 230 includes a plurality of vertical ribs 233. The vertical rib 233 is fixedly connected to the inner surface of the lamp tube 1 on one end and to the LED light strip 2 on the other end. The LED light assembly may be spaced apart from the inner surface of the plastic lamp tube 1. The plastic lamp tube 1 is protected from heat generated by the LED light assembly because the heat is taken away from the lamp tube 1 by the plurality of the vertical ribs 233. A cross section of the lamp tube 1 cuts through an LED light source 202, a first vertical rib 233 connected to an upper surface of the LED light assembly, a second vertical rib 233 connected to a lower surface of the LED light assembly or any combination of the above. In some embodiments, the LED light assembly, the first vertical rib 233 and the second vertical rib 233 may be aligned with one another, or alternatively, may be staggered. In an embodiment, the second vertical rib 233 connected to the lower surface of the LED light assembly is an unbroken structure extending along the longitudinal axis of the lamp tube 1 for better heat dissipation and more structural strength. In FIG. 10, the plurality of first vertical ribs 233 are spaced apart from one another like an array of pillars. However, the second vertical rib 233 extends uninterruptedly between the lower surface of the LED light assembly and the lamp tube 1 like a wall.

Turning to FIG. 11, in accordance with an exemplary embodiment, the reinforcing portion 230 further includes a platform. The vertical rib 233 is fixedly connected to, instead of the LED light assembly, the platform on one end and to the inner surface on the other end. The vertical ribs 233 and the platform may be one integral structure. The LED light assembly is thermally connected to an upper surface of the platform.

The position of the LED light strip 2 inside the lamp tube 1—i.e. the length of the first vertical rib 233 and the length of the second vertical rib 233—is chosen in light of one or more factors such as, for example, field angle, heat-dissipating capability and structural strength. In FIGS. 9 and 11, the ratio of the distance (H) between the LED light strip 2 and the dome of the lamp tube 1 to the diameter of the lamp tube 1 may be, for example, from 0.25 to 0.9. In some embodiments, the ratio of the distance (H) between the LED light strip 2 and the dome of the lamp tube 1 to the diameter of the lamp tube 1 may be from 0.33 to 0.75.

In an embodiment, the LED light strip is made from flexible substrate material. Referring to FIGS. 12 and 13, in accordance with an exemplary embodiment, the flexible LED light strip 2 includes a wiring layer 2 a. The wiring layer 2 a is an electrically conductive layer, e.g. a metallic layer or a layer of copper wire, and is electrically connected to the power supply. The LED light source 202 is disposed on and electrically connected to a first surface of the wiring layer 2 a. Turning to FIGS. 16 and 17, the LED light strip 2 further includes a dielectric layer 2 b. The dielectric layer 2 b is disposed on a second surface of the wiring layer 2 a. The dielectric layer 2 b has a different surface area than the wiring layer 2 a. The LED light source 202 is disposed on a surface of the wiring layer 2 a which is opposite to the other surface of the wiring layer 2 a which is adjacent to the dielectric layer 2 b. The wiring layer 2 a can be a metal layer or a layer having wires such as copper wires.

In an embodiment, the LED light strip 2 further includes a protection layer over the wiring layer 2 a and the dielectric layer 2 b. The protection layer is made from one of solder resists such as, for example, a liquid photoimageable resist.

In another embodiment, as shown in FIGS. 14 and 15, the outer surface of the wiring layer 2 a or the dielectric layer 2 b (i.e. the two layered structure) may be covered with a circuit protective layer 2 c made of an ink with function of resisting soldering and increasing reflectivity. Alternatively, the dielectric layer 2 b can be omitted and the wiring layer 2 a can be directly bonded to the inner circumferential surface of the lamp tube (i.e. the one-layered structure), and the outer surface of the wiring layer 2 a is coated with the circuit protective layer 2 c. As shown in FIGS. 14 and 15, the circuit protective layer 2 c is formed with openings such that the LED light sources 202 are electrically connected to the wiring layer 2 a. Whether the one-layered or the two-layered structure is used, the circuit protective layer 2 c can be adopted. The bendable circuit sheet is a one-layered structure made of just one wiring layer 2 a, or a two-layered structure made of one wiring layer 2 a and one dielectric layer 2 b, and may be more bendable or flexible to curl when compared with the conventional three-layered flexible substrate (one dielectric layer sandwiched with two wiring layers). As a result, the bendable circuit sheet of the LED light strip 2 can be installed in a lamp tube with a customized shape or non-tubular shape, and fitly mounted to the inner surface of the lamp tube. In some embodiments, the bendable circuit sheet may be closely mounted to the inner surface of the lamp tube. In addition, using fewer layers of the bendable circuit sheet improves the heat dissipation and lowers the material cost.

In some embodiments, any type of power supply 5 can be electrically connected to the LED light strip 2 by means of a traditional wire bonding technique, in which a metal wire has an end connected to the power supply 5 while has the other end connected to the LED light strip 2. Furthermore, the metal wire may be wrapped with an electrically insulating tube to protect a user from being electrically shocked. However, the bonded wires tend to be easily broken during transportation and can therefore cause quality issues.

In still another embodiment, the connection between the power supply 5 and the LED light strip 2 may be accomplished via soldering (e.g., tin soldering), rivet bonding, or welding. One way to secure the LED light strip 2 is to provide the adhesive sheet at one side thereof and adhere the LED light strip 2 to the inner surface of the lamp tube 1 via the adhesive sheet. Two ends of the LED light strip 2 can be either fixed to or detached from the inner surface of the lamp tube 1.

In embodiments where two ends of the LED light strip 2 are fixed to the inner surface of the lamp tube 1, the bendable circuit sheet of the LED light strip 2 may be provided with the female plug and the power supply is provided with the male plug to accomplish the connection between the LED light strip 2 and the power supply 5. In this case, the male plug of the power supply is inserted into the female plug to establish electrical connection.

In embodiments where two ends of the LED light strip 2 are detached from the inner surface of the lamp tube and that the LED light strip 2 is connected to the power supply 5 via wire-bonding, movement during subsequent transportation is likely to cause the bonded wires to break. Therefore, in some embodiments, the connection between the light strip 2 and the power supply 5 could be soldering. Specifically, the ends of the LED light strip 2 including the bendable circuit sheet are arranged to pass over the strengthened transition region and be directly solder bonded to an output terminal of the power supply 5 such that the product quality is improved without using wires. In this way, the female plug and the male plug respectively provided for the LED light strip 2 and the power supply 5 are no longer needed.

Referring to FIG. 18, an output terminal of the printed circuit board of the power supply 5 may have soldering pads “a” provided with an amount of tin solder with a thickness sufficient to later form a solder joint. Correspondingly, the ends of the LED light strip 2 may have soldering pads “b”. The soldering pads “a” on the output terminal of the printed circuit board of the power supply 5 are soldered to the soldering pads “b” on the LED light strip 2 via the tin solder on the soldering pads “a”. The soldering pads “a” and the soldering pads “b” may be face to face during soldering such that the connection between the LED light strip 2 and the printed circuit board of the power supply 5 is the most firm. However, with this kind of soldering, a thermo-compression head presses on the rear surface of the LED light strip 2 and heats the tin solder, i.e. the LED light strip 2 intervenes between the thermo-compression head and the tin solder, and therefor may cause reliability issues. Referring to FIG. 24, a through hole may be formed in each of the soldering pads “b” on the LED light strip 2 to allow the soldering pads “b” overlay the soldering pads “b” without face-to-face and the thermo-compression head directly presses tin solders on the soldering pads “a” on surface of the printed circuit board of the power supply 5 when the soldering pads “a” and the soldering pads “b” are vertically aligned.

Referring again to FIG. 18, two ends of the LED light strip 2 detached from the inner surface of the lamp tube 1 are formed as freely extending portions 21, while most of the LED light strip 2 is attached and secured to the inner surface of the lamp tube 1. One of the freely extending portions 21 has the soldering pads “b” as mentioned above. Upon assembling of the LED tube lamp, the freely extending end portions 21 along with the soldered connection of the printed circuit board of the power supply 5 and the LED light strip 2 would be coiled, curled up or deformed to be fittingly accommodated inside the lamp tube 1. For example, the freely extending portions may bend away from the inner surface of the lamp tube 1.

In this embodiment, during the connection of the LED light strip 2 and the power supply 5, the soldering pads “b” and the soldering pads “a” and the LED light sources 202 are on surfaces facing toward the same direction and the soldering pads “b” on the LED light strip 2 are each formed with a through hole “e” as shown in FIG. 24 such that the soldering pads “b” and the soldering pads “a” communicate with each other via the through holes “e”. When the freely extending end portions 21 are deformed due to contraction or curling up, the soldered connection of the printed circuit board of the power supply 5 and the LED light strip 2 exerts a lateral tension on the power supply 5. Furthermore, the soldered connection of the printed circuit board of the power supply 5 and the LED light strip 2 also exerts a downward tension on the power supply 5 when compared with the situation where the soldering pads “a” of the power supply 5 and the soldering pads “b” of the LED light strip 2 are face to face. This downward tension on the power supply 5 comes from the tin solders inside the through holes “e” and forms a stronger and more secure electrical connection between the LED light strip 2 and the power supply 5.

Referring to FIG. 19, in one embodiment, the soldering pads “b” of the LED light strip 2 are two separate pads to electrically connect the positive and negative electrodes of the bendable circuit sheet of the LED light strip 2, respectively. The size of the soldering pads “b” may be, for example, about 3.5×2 mm2. The printed circuit board of the power supply 5 is correspondingly provided with soldering pads “a” having reserved tin solders and the height of the tin solders suitable for subsequent automatic soldering bonding process may be generally, for example, about 0.1 to 0.7 mm, in some embodiments 0.3 to 0.5 mm. In some exemplary embodiments, the height of the tin solders suitable for subsequent automatic solder bonding process may be about 0.4 mm. An electrically insulating through hole “c” may be formed between the two soldering pads “b” to isolate and prevent the two soldering pads from electrically short during soldering. Furthermore, an extra positioning opening “d” may also be provided behind the electrically insulating through hole “c” to allow an automatic soldering machine to quickly recognize the position of the soldering pads “b”.

There is at least one soldering pad “b” for separately connecting to the positive and negative electrodes of the LED light sources 202. For the sake of achieving scalability and compatibility, the amount of the soldering pads “b” on each end of the LED light strip 2 may be more than one such as two, three, four, or more than four. When there is only one soldering pad “b” provided at each end of the LED light strip 2, the two ends of the LED light strip 2 are electrically connected to the power supply 5 to form a loop, and various electrical components can be used. For example, a capacitance may be replaced by an inductance to perform current regulation. Referring to FIGS. 20 to 23, when each end of the LED light strip 2 has three soldering pads, the third soldering pad can be grounded; when each end of the LED light strip 2 has four soldering pads, the fourth soldering pad can be used as a signal input terminal. Correspondingly, the power supply 5 has the same amount of soldering pads “a” as that of the soldering pads “b” on the LED light strip 2. As long as electrical shorts between the soldering pads “b” can be prevented, the soldering pads “b” may be arranged according to the dimension of the actual area for disposition, for example, three soldering pads can be arranged in a row or two rows. In other embodiments, the amount of the soldering pads “b” on the bendable circuit sheet of the LED light strip 2 may be reduced by rearranging the circuits on the bendable circuit sheet of the LED light strip 2. The lesser the amount of the soldering pads, the easier the fabrication process becomes. On the other hand, a greater number of soldering pads may improve and secure the electrical connection between the LED light strip 2 and the output terminal of the power supply 5.

Referring to FIG. 24, in another embodiment, each soldering pad “b” is formed with a through hole “e” having a diameter generally of about 1 to 2 mm, in some embodiments of about 1.2 to 1.8 mm, and in yet some embodiments of about 1.5 mm. The through hole “e” communicates the soldering pad “a” with the soldering pad “b” so that the tin solder on the soldering pads “a” passes through the through holes “e” and finally reach the soldering pads “b”. A smaller through holes “e” would make it difficult for the tin solder to pass. The tin solder accumulates around the through holes “e” upon exiting the through holes “e” and condense to form a solder ball “g” with a larger diameter than that of the through holes “e” upon condensing. Such a solder ball “g” functions as a rivet to further increase the stability of the electrical connection between the soldering pads “a” on the power supply 5 and the soldering pads “b” on the LED light strip 2.

Referring to FIGS. 25 to 26, in other embodiments, when a distance from the through hole “e” to the side edge of the LED light strip 2 is less than 1 mm, the tin solder may pass through the through hole “e” to accumulate on the periphery of the through hole “e”, and extra tin solder may spill over the soldering pads “b” to reflow along the side edge of the LED light strip 2 and join the tin solder on the soldering pads “a” of the power supply 5. The tin solder then condenses to form a structure like a rivet to firmly secure the LED light strip 2 onto the printed circuit board of the power supply 5 such that reliable electric connection is achieved. Referring to FIG. 27 and FIG. 28, in another embodiment, the through hole “e” can be replaced by a notch “f” formed at the side edge of the soldering pads “b” for the tin solder to easily pass through the notch “f” and accumulate on the periphery of the notch “f” and to form a solder ball with a larger diameter than that of the notch “e” upon condensing. Such a solder ball may be formed like a C-shape rivet to enhance the secure capability of the electrically connecting structure.

The abovementioned through hole “e” or notch “f” might be formed in advance of soldering or formed by direct punching with a thermo-compression head during soldering. The portion of the thermo-compression head for touching the tin solder may be flat, concave, or convex, or any combination thereof. The portion of the thermo-compression head for restraining the object to be soldered such as the LED light strip 2 may be strip-like or grid-like. The portion of the thermo-compression head for touching the tin solder does not completely cover the through hole “e” or the notch “f” to make sure that the tin solder is able to pass through the through hole “e” or the notch “f”. The portion of the thermo-compression head being concave may function as a room to receive the solder ball.

The power supply 5 is electrically coupled to the LED light strip 2 and the features and applications of the related power supply assembly are described below. In some embodiments, the circuits and the assemblies mentioned below may be all disposed on the reinforcing portion in the lamp tube to increase the heat dissipating area and efficiency, simplify the circuit design in the end cap, and provides an easier control for the length of the lamp tube in manufacturing. Or, some of them are kept in the end cap (e.g. resistors, or capacitors, or the components with smaller volume or smaller power consumption, the components generating less heat or having better heat resistant) and the others are disposed on the reinforcing portion (e.g. chips, inductors, transistors, or the components with bigger volume, the components generating much heat or having poor heat resistant) so as to increase the heat dissipating area and efficiency and simplify the circuit design in the end cap. The implementations are not limited to the disclosed embodiments.

In some embodiments, for example, the circuits and the assemblies disposed on the reinforcing portion in the lamp tube may be implemented by surface mount components. Some of the circuits and the assemblies may be disposed on the LED light strip and then electrically connected to the circuit(s) kept in the end cap via male-female plug or wire with insulating coating/layer for achieving the isolation effect. Or, the circuits and the assemblies related to the power supply may all be disposed on the LED light strip to reduce the reserved length of the LED light strip, which is used for connecting to other circuit board(s), and also to reduce the allowable error length and omit the process for electrically connecting two or more circuit boards, so that the lengths of the lamp tube and the LED light strip could be controlled more precisely. The circuits and the assemblies and the LEDs may be disposed on the same or different side of the reinforcing portion. In some embodiments, the circuits and the assemblies and the LEDs may be disposed on the same side to reduce the process of making through hole(s) on the reinforcing portion for electrically connection. The implementations are not limited to the disclosed embodiments.

Next, examples of the circuit design and using of the power supply module 250 are described as follows.

FIG. 29A is a block diagram of a power supply system for an LED tube lamp according to an embodiment. Referring to FIG. 29A, an AC power supply 508 is used to supply an AC supply signal, and may be an AC powerline with a voltage rating, for example, in 100-277 volts and a frequency rating, for example, of 50 or 60 Hz. A lamp driving circuit 505 receives and then converts the AC supply signal into an AC driving signal as an external driving signal. Lamp driving circuit 505 may be, for example, an electronic ballast used to convert the AC powerline into a high-frequency high-voltage AC driving signal. Common types of electronic ballast include instant-start ballast, program-start or rapid-start ballast, etc., which may all be applicable to the LED tube lamp of the present disclosure. The voltage of the AC driving signal may be higher than 300 volts, and is in some embodiments in the range of about 400-700 volts. The frequency of the AC driving signal may be higher than 10 k Hz, and is in some embodiments in the range of about 20 k-50 k Hz. The LED tube lamp 500 receives an external driving signal and is thus driven to emit light. In one embodiment, the external driving signal comprises the AC driving signal from lamp driving circuit 505. In one embodiment, LED tube lamp 500 is in a driving environment in which pins 501 and 502 are respectively disposed at the two opposite end caps of LED tube lamp 500, forming a single pin at each end of LED tube lamp 500 to receive the AC driving signal. The two conductive pins 501 and 502 may be electrically connected to, either directly or indirectly, the lamp driving circuit 505.

In some embodiments, lamp driving circuit 505 may be omitted and is therefore depicted by a dotted line. In one embodiment, if lamp driving circuit 505 is omitted, AC power supply 508 is directly connected to pins 501 and 502, which then receive the AC supply signal as an external driving signal.

FIG. 29B is a block diagram of an LED lamp according to one embodiment. Referring to FIG. 29B, the power supply module of the LED lamp summarily includes a rectifying circuit 510, and a filtering circuit 520, and may comprise a portion of an LED lighting module 530. Rectifying circuit 510 is coupled to pins 501 and 502 to receive and then rectify an external driving signal, so as to output a rectified signal at output terminals 511 and 512. The external driving signal may be the AC driving signal or the AC supply signal described with reference to FIG. 29A, or may be a DC signal, which embodiments do not alter the LED lamp of the present disclosure. Filtering circuit 520 is coupled to the first rectifying circuit for filtering the rectified signal to produce a filtered signal, as recited in the claims. For instance, filtering circuit 520 is coupled to terminals 511 and 512 to receive and then filter the rectified signal, so as to output a filtered signal at filtering output terminals 521 and 522. LED lighting module 530 is coupled to filtering circuit 520, to receive the filtered signal for emitting light. For instance, LED lighting module 530 may be a circuit coupled to filtering output terminals 521 and 522 to receive the filtered signal and thereby to drive an LED unit (not shown) in LED lighting module 530 to emit light. Details of these operations are described in below descriptions of certain embodiments.

Although there are two output terminals 511 and 512 and two filtering output terminals 521 and 522 in embodiments of these Figs., in practice the number of ports or terminals for coupling between rectifying circuit 510, filtering circuit 520, and LED lighting module 530 may be one or more depending on the needs of signal transmission between the circuits or devices.

In addition, the power supply module of the LED lamp described in FIG. 29B, and embodiments of the power supply module of an LED lamp described below, may each be used in the LED tube lamp 500 in FIG. 29A, and may instead be used in any other type of LED lighting structure having two conductive pins used to conduct power, such as LED light bulbs, personal area lights (PAL), plug-in LED lamps with different types of bases (such as types of PL-S, PL-D, PL-T, PL-L, etc.), etc.

FIG. 29C is a block diagram of a power supply system for an LED tube lamp according to an embodiment. Referring to FIG. 29C, an AC power supply 508 is used to supply an AC supply signal. A lamp driving circuit 505 receives and then converts the AC supply signal into an AC driving signal. An LED tube lamp 500 receives an AC driving signal from lamp driving circuit 505 and is thus driven to emit light. In this embodiment, LED tube lamp 500 is power-supplied at its both end caps respectively having two pins 501 and 502 and two pins 503 and 504, which are coupled to lamp driving circuit 505 to concurrently receive the AC driving signal to drive an LED unit (not shown) in LED tube lamp 500 to emit light. AC power supply 508 may be e.g. the AC powerline, and lamp driving circuit 505 may be a stabilizer or an electronic ballast.

FIG. 29D is a block diagram of an LED lamp according to an embodiment.

Referring to FIG. 29D, the power supply module of the LED lamp summarily includes a rectifying circuit 510, a filtering circuit 520, and a filtering circuit 540 and may comprise a portion of an LED lighting module 530. Rectifying circuit 510 is coupled to pins 501 and 502 to receive and then rectify an external driving signal conducted by pins 501 and 502. Rectifying circuit 540 is coupled to pins 503 and 504 to receive and then rectify an external driving signal conducted by pins 503 and 504. Therefore, the power supply module of the LED lamp may include two rectifying circuits 510 and 540 configured to output a rectified signal at output terminals 511 and 512. Filtering circuit 520 is coupled to terminals 511 and 512 to receive and then filter the rectified signal, so as to output a filtered signal at filtering output terminals 521 and 522. LED lighting module 530 is coupled to filtering output terminals 521 and 522 to receive the filtered signal and thereby to drive an LED unit (not shown) in LED lighting module 530 to emit light.

The power supply module of the LED lamp in this embodiment of FIG. 29D may be used in LED tube lamp 500 with a dual-end power supply in FIG. 29C. In some embodiments, since the power supply module of the LED lamp comprises rectifying circuits 510 and 540, the power supply module of the LED lamp may be used in LED tube lamp 500 with a single-end power supply in FIG. 29A, to receive an external driving signal (such as the AC supply signal or the AC driving signal described above). The power supply module of an LED lamp in this embodiment and other embodiments herein may also be used with a DC driving signal.

FIG. 30A is a schematic diagram of a rectifying circuit according to an exemplary embodiment. Referring to FIG. 30A, rectifying circuit 610 includes rectifying diodes 611, 612, 613, and 614, configured to full-wave rectify a received signal. Diode 611 has an anode connected to output terminal 512, and a cathode connected to pin 502. Diode 612 has an anode connected to output terminal 512, and a cathode connected to pin 501. Diode 613 has an anode connected to pin 502, and a cathode connected to output terminal 511. Diode 614 has an anode connected to pin 501, and a cathode connected to output terminal 511.

When pins 501 and 502 receive an AC signal, rectifying circuit 610 operates as follows. During the connected AC signal's positive half cycle, the AC signal is input through pin 501, diode 614, and output terminal 511 in sequence, and later output through output terminal 512, diode 611, and pin 502 in sequence. During the connected AC signal's negative half cycle, the AC signal is input through pin 502, diode 613, and output terminal 511 in sequence, and later output through output terminal 512, diode 612, and pin 501 in sequence. Therefore, during the connected AC signal's full cycle, the positive pole of the rectified signal produced by rectifying circuit 610 remains at output terminal 511, and the negative pole of the rectified signal remains at output terminal 512. Accordingly, the rectified signal produced or output by rectifying circuit 610 is a full-wave rectified signal.

When pins 501 and 502 are coupled to a DC power supply to receive a DC signal, rectifying circuit 610 operates as follows. When pin 501 is coupled to the anode of the DC supply and pin 502 is coupled to the cathode of the DC supply, the DC signal is sequentially input through pin 501, diode 614, and output terminal 511, and later sequentially output through output terminal 512, diode 611, and pin 502. When pin 501 is coupled to the cathode of the DC supply and pin 502 to the anode of the DC supply, the DC signal is sequentially input through pin 502, diode 613, and output terminal 511, and later output through output terminal 512, diode 612, and pin 501 in sequence. Therefore, no matter what the electrical polarity of the DC signal is between pins 501 and 502, the positive pole of the rectified signal produced by rectifying circuit 610 remains at output terminal 511, and the negative pole of the rectified signal remains at output terminal 512.

Therefore, rectifying circuit 610 in this embodiment can output or produce a proper rectified signal regardless of whether the received input signal is an AC or DC signal.

FIG. 30B is a schematic diagram of a rectifying circuit according to an exemplary embodiment. Referring to FIG. 30B, rectifying circuit 710 includes rectifying diodes 711 and 712, configured to half-wave rectify a received signal. Diode 711 has an anode connected to pin 502, and a cathode connected to output terminal 511. Diode 712 has an anode connected to output terminal 511, and a cathode connected to pin 501. Output terminal 512 may be omitted or grounded depending on actual applications.

Next, exemplary operation(s) of rectifying circuit 710 is described as follows.

In one embodiment, during a received AC signal's positive half cycle, the electrical potential at pin 501 is higher than that at pin 502, so diodes 711 and 712 are both in a cutoff state as being reverse-biased, making rectifying circuit 710 not outputting a rectified signal. During a received AC signal's negative half cycle, the electrical potential at pin 501 is lower than that at pin 502, so diodes 711 and 712 are both in a conducting state as being forward-biased, allowing the AC signal to be input through diode 711 and output terminal 511, and later output through output terminal 512, a ground terminal, or another end of the LED tube lamp not directly connected to rectifying circuit 710. Accordingly, the rectified signal produced or output by rectifying circuit 710 is a half-wave rectified signal.

Rectifying circuit 510 as shown and explained in FIG. 30A-FIG. 30B can constitute or be the rectifying circuit 540 shown in FIG. 29D, as having pins 503 and 504 for conducting instead of pins 501 and 502.

Next, an explanation follows as to choosing embodiments and their combinations of rectifying circuits 510 and 540, with reference to FIG. 29B and FIG. 29D.

Rectifying circuit 510 in embodiments shown in FIG. 29B may comprise the rectifying circuit 610 in FIG. 30A.

Rectifying circuits 510 and 540 in embodiments shown in FIG. 29D may each comprise any one of the rectifying circuits in FIG. 30A-FIG. 30B may be omitted without altering the rectification function of an LED tube lamp. When rectifying circuits 510 and 540 each comprise a half-wave rectifier circuit described in FIG. 30B, during a received AC signal's positive or negative half cycle, the AC signal may be input from one of rectifying circuits 510 and 540, and later output from the other rectifying circuit 510 or 540.

FIG. 31A is a block diagram of the filtering circuit according to an exemplary embodiment. Rectifying circuit 510 is shown in FIG. 31A for illustrating its connection with other components, without intending filtering circuit 520 to include rectifying circuit 510. Referring to FIG. 31A, filtering circuit 520 includes a filtering unit 523 coupled to rectifying output terminals 511 and 512 to receive, and to filter out ripples of, a rectified signal from rectifying circuit 510, thereby outputting a filtered signal whose waveform is smoother than the rectified signal. Filtering circuit 520 may further comprise another filtering unit 524 coupled between a rectifying circuit and a pin, which are for example rectifying circuit 510 and pin 501, rectifying circuit 510 and pin 502, rectifying circuit 540 and pin 503, or rectifying circuit 540 and pin 504. Filtering unit 524 is for filtering of a specific frequency, in order to filter out a specific frequency component of an external driving signal. In this embodiment of FIG. 31A, filtering unit 524 is coupled between rectifying circuit 510 and pin 501. Filtering circuit 520 may further comprise another filtering unit 525 coupled between one of pins 501 and 502 and a diode of rectifying circuit 510, or between one of pins 503 and 504 and a diode of rectifying circuit 540, for reducing or filtering out electromagnetic interference (EMI). In this embodiment, filtering unit 525 is coupled between pin 501 and a diode (not shown in FIG. 31A) of rectifying circuit 510. Since filtering units 524 and 525 may be present or omitted depending on actual circumstances of their uses, they are depicted by a dotted line in FIG. 31A.

FIG. 31B is a schematic diagram of the filtering unit according to an exemplary embodiment. Referring to FIG. 31B, filtering unit 623 includes a capacitor 625 having an end coupled to output terminal 511 and a filtering output terminal 521 and another end coupled to output terminal 512 and a filtering output terminal 522, and is configured to low-pass filter a rectified signal from output terminals 511 and 512, so as to filter out high-frequency components of the rectified signal and thereby output a filtered signal at filtering output terminals 521 and 522.

FIG. 31C is a schematic diagram of the filtering unit according to an exemplary embodiment. Referring to FIG. 31C, filtering unit 723 comprises a pi filter circuit including a capacitor 725, an inductor 726, and a capacitor 727. As is well known, a pi filter circuit looks like the symbol 7 in its shape or structure. Capacitor 725 has an end connected to output terminal 511 and coupled to output terminal 521 through inductor 726, and has another end connected to output terminals 512 and 522. Inductor 726 is coupled between output terminals 511 and 521. Capacitor 727 has an end connected to output terminal 521 and coupled to output terminal 511 through inductor 726, and has another end connected to output terminals 512 and 522.

As seen between output terminals 511 and 512 and output terminals 521 and 522, filtering unit 723 compared to filtering unit 623 in FIG. 31B additionally has inductor 726 and capacitor 727, which are like capacitor 725 in performing low-pass filtering. Therefore, filtering unit 723 in this embodiment compared to filtering unit 623 in FIG. 31B has a better ability to filter out high-frequency components to output a filtered signal with a smoother waveform.

In the exemplary embodiments described above, inductance values of inductor 726 may be in the range of, for example, about 10 nH to about 10 mH. And, in the embodiments described above, capacitance values of capacitors 625, 725, and 727 may be in the range of, for example, about 100 pF to about 1 uF.

FIG. 31D is a schematic diagram of the filtering unit according to an exemplary embodiment. Referring to FIG. 31D, filtering unit 824 includes a capacitor 825 and an inductor 828 connected in parallel. Capacitor 825 has an end coupled to pin 501, and another end coupled to rectifying output terminal 511, and is configured to high-pass filter an external driving signal input at pin 501, so as to filter out low-frequency components of the external driving signal. Inductor 828 has an end coupled to pin 501 and another end coupled to rectifying output terminal 511, and is configured to low-pass filter an external driving signal input at pin 501, so as to filter out high-frequency components of the external driving signal. Therefore, the combination of capacitor 825 and inductor 828 works to present high impedance to an external driving signal at one or more specific frequencies. Thus, the parallel-connected capacitor and inductor work to present a peak equivalent impedance to the external driving signal at a specific frequency.

Through appropriately choosing a capacitance value of capacitor 825 and an inductance value of inductor 828, a center frequency f on the high-impedance band may be set at a specific value given by

${f = \frac{1}{2\pi\sqrt{LC}}},$ where L denotes inductance of inductor 828 and C denotes capacitance of capacitor 825. The center frequency is, in some embodiments, in the range of about 20˜30 kHz. In certain embodiments, the center frequency may be about 25 kHz. And an LED lamp with filtering unit 824 is able to be certified under safety standards, for a specific center frequency, as provided by Underwriters Laboratories (UL).

In some embodiments, filtering unit 824 may further comprise a resistor 829, coupled between pin 501 and filtering output terminal 511. In FIG. 31D, resistor 829 is connected in series to the parallel-connected capacitor 825 and inductor 828. For example, resistor 829 may be coupled between pin 501 and parallel-connected capacitor 825 and inductor 828, or may be coupled between filtering output terminal 511 and parallel-connected capacitor 825 and inductor 828. In this embodiment, resistor 829 is coupled between pin 501 and parallel-connected capacitor 825 and inductor 828. Further, resistor 829 is configured for adjusting the quality factor (Q) of the LC circuit comprising capacitor 825 and inductor 828, to better adapt filtering unit 824 to application environments with different quality factor requirements. Since resistor 829 is an optional component, it is depicted in a dotted line in FIG. 31D.

Capacitance values of capacitor 825 are, in some embodiments, in the range of about 10 nF-2 uF. Inductance values of inductor 828 are, in some embodiments, smaller than 2 mH. In certain embodiments, inductance values of inductor 828 may be smaller than 1 mH. Resistance values of resistor 829 are, in some embodiments, larger than 50 ohms. In certain embodiments, resistance values of resistor 829 may be larger than 500 ohms.

In addition or as an alternative to the filtering circuits shown and described in the above embodiments, traditional low-pass or band-pass filters can be used as the filtering unit in the filtering circuit in the present disclosure.

FIG. 31E is a schematic diagram of the filtering unit according to an exemplary embodiment. Referring to FIG. 31E, in this embodiment filtering unit 925 is disposed in rectifying circuit 610 as shown in FIG. 30A, and is configured for reducing the EMI (Electromagnetic interference) caused by rectifying circuit 610 and/or other circuits. In this embodiment, filtering unit 925 includes an EMI-reducing capacitor coupled between pin 501 and the anode of rectifying diode 613, and also between pin 502 and the anode of rectifying diode 614, to reduce the EMI associated with the positive half cycle of the AC driving signal received at pins 501 and 502. The EMI-reducing capacitor of filtering unit 925 is also coupled between pin 501 and the cathode of rectifying diode 611, and between pin 502 and the cathode of rectifying diode 612, to reduce the EMI associated with the negative half cycle of the AC driving signal received at pins 501 and 502. In some embodiments, rectifying circuit 610 comprises a full-wave bridge rectifier circuit including four rectifying diodes 611, 612, 613, and 614. The full-wave bridge rectifier circuit has a first filtering node connecting an anode and a cathode respectively of two diodes 613 and 611 of the four rectifying diodes 611, 612, 613, and 614, and a second filtering node connecting an anode and a cathode respectively of the other two diodes 614 and 612 of the four rectifying diodes 611, 612, 613, and 614. And the EMI-reducing capacitor of the filtering unit 925 is coupled between the first filtering node and the second filtering node.

The EMI-reducing capacitor in the embodiment of FIG. 31E may also act as capacitor 825 in filtering unit 824, so that in combination with inductor 828 the capacitor 825 performs the functions of reducing EMI and presenting high impedance to an external driving signal at specific frequencies. For example, when the rectifying circuit comprises a full-wave bridge rectifier circuit, capacitor 825 of filtering unit 824 may be coupled between the first filtering node and the second filtering node of the full-wave bridge rectifier circuit. When the rectifying circuit comprises a half-wave rectifier circuit, capacitor 825 of filtering unit 824 may be coupled between the half-wave node of the half-wave rectifier circuit and at least one of the first pin and the second pin.

FIG. 32A is a schematic diagram of an LED module according to an exemplary embodiment. Referring to FIG. 32A, LED module 630 has an anode connected to the filtering output terminal 521, has a cathode connected to the filtering output terminal 522, and comprises at least one LED unit 632. When two or more LED units are included, they are connected in parallel. The anode of each LED unit 632 is connected to the anode of LED module 630 and thus output terminal 521, and the cathode of each LED unit 632 is connected to the cathode of LED module 630 and thus output terminal 522. Each LED unit 632 includes at least one LED 631. When multiple LEDs 631 are included in an LED unit 632, they are connected in series, with the anode of the first LED 631 connected to the anode of this LED unit 632, and the cathode of the first LED 631 connected to the next or second LED 631. And the anode of the last LED 631 in this LED unit 632 is connected to the cathode of a previous LED 631, with the cathode of the last LED 631 connected to the cathode of this LED unit 632.

In some embodiments, LED module 630 may produce a current detection signal S531 reflecting a magnitude of current through LED module 630 and used for controlling or detecting on the LED module 630.

FIG. 32B is a schematic diagram of an LED module according to an exemplary embodiment. Referring to FIG. 32B, LED module 630 has an anode connected to the filtering output terminal 521, has a cathode connected to the filtering output terminal 522, and comprises at least two LED units 732, with the anode of each LED unit 732 connected to the anode of LED module 630, and the cathode of each LED unit 732 connected to the cathode of LED module 630. Each LED unit 732 includes at least two LEDs 731 connected in the same way as described in FIG. 32A. For example, the anode of the first LED 731 in an LED unit 732 is connected to the anode of this LED unit 732, the cathode of the first LED 731 is connected to the anode of the next or second LED 731, and the cathode of the last LED 731 is connected to the cathode of this LED unit 732. Further, LED units 732 in an LED module 630 are connected to each other in this embodiment. For example, all of the n-th LEDs 731 of the respective LED units 732 may be connected with every anode of every n-th LED 731 in the LED units 732, and by every cathode of every n-th LED 731, where n is a positive integer. In this way, the LEDs in LED module 630 in this embodiment are connected in the form of a mesh.

Compared to the embodiments of FIG. 33A to FIG. 33G, LED lighting module 530 of the above embodiments includes LED module 630, but doesn't include a driving circuit for the LED module 630.

Similarly, LED module 630 in this embodiment may produce a current detection signal S531 reflecting a magnitude of current through LED module 630 and used for controlling or detecting on the LED module 630.

In actual practice, the number of LEDs 731 included by an LED unit 732 is, in some embodiments, in the range of 15-25. In certain embodiments, the number of LEDs 731 included by an LED unit 732 may be in the range of 18-22.

FIG. 32C is a plan view of a circuit layout of the LED module according to an exemplary embodiment. Referring to FIG. 32C, in this embodiment LEDs 831 are connected in the same way as described in FIG. 32B, and three LED units are assumed in LED module 630 and described as follows for illustration. A positive conductive line 834 and a negative conductive line 835 are to receive a driving signal, for supplying power to the LEDs 831. For example, positive conductive line 834 may be coupled to the filtering output terminal 521 of the filtering circuit 520 described above, and negative conductive line 835 coupled to the filtering output terminal 522 of the filtering circuit 520, to receive a filtered signal. For the convenience of illustration, all three of the n-th LEDs 831 respectively of the three LED units are grouped as an LED set 833 in FIG. 32C.

Positive conductive line 834 connects the three first LEDs 831 respectively of the leftmost three LED units, at the anodes on the left sides of the three first LEDs 831, as shown in the leftmost LED set 833 of FIG. 32C. Negative conductive line 835 connects the three last LEDs 831 respectively of the leftmost three LED units, at the cathodes on the right sides of the three last LEDs 831, as shown in the rightmost LED set 833 of FIG. 32C. And of the three LED units, the cathodes of the three first LEDs 831, the anodes of the three last LEDs 831, and the anodes and cathodes of all the remaining LEDs 831 are connected by conductive lines or parts 839.

For example, the anodes of the three LEDs 831 in the leftmost LED set 833 may be connected together by positive conductive line 834, and their cathodes may be connected together by a leftmost conductive part 839. The anodes of the three LEDs 831 in the second leftmost LED set 833 are also connected together by the leftmost conductive part 839, whereas their cathodes are connected together by a second leftmost conductive part 839. Since the cathodes of the three LEDs 831 in the leftmost LED set 833 and the anodes of the three LEDs 831 in the second leftmost LED set 833 are connected together by the same leftmost conductive part 839, in each of the three LED units the cathode of the first LED 831 is connected to the anode of the next or second LED 831, with the remaining LEDs 831 also being connected in the same way. Accordingly, all the LEDs 831 of the three LED units are connected to form the mesh as shown in FIG. 32B.

In this exemplary embodiment, the length 836 of a portion of each conductive part 839 that immediately connects to the anode of an LED 831 is smaller than the length 837 of another portion of each conductive part 839 that immediately connects to the cathode of an LED 831, making the area of the latter portion immediately connecting to the cathode larger than that of the former portion immediately connecting to the anode. The length 837 may be smaller than a length 838 of a portion of each conductive part 839 that immediately connects the cathode of an LED 831 and the anode of the next LED 831, making the area of the portion of each conductive part 839 that immediately connects a cathode and an anode larger than the area of any other portion of each conductive part 839 that immediately connects to only a cathode or an anode of an LED 831. Due to the length differences and area differences, this layout structure improves heat dissipation of the LEDs 831.

In some embodiments, positive conductive line 834 includes a lengthwise portion 834 a, and negative conductive line 835 includes a lengthwise portion 835 a, which are conducive to making the LED module have a positive “+” connective portion and a negative “−” connective portion at each of the two ends of the LED module, as shown in FIG. 32C. Such a layout structure allows for coupling any of other circuits of the power supply module of the LED lamp, including e.g. filtering circuit 520 and rectifying circuits 510 and 540, to the LED module through the positive connective portion and/or the negative connective portion at each or both ends of the LED lamp. In some embodiments, the layout structure increases the flexibility in arranging actual circuits in the LED lamp.

FIG. 32D is a plan view of a circuit layout of the LED module according to another exemplary embodiment. Referring to FIG. 32D, in this embodiment LEDs 931 are connected in the same way as described in FIG. 32A, and three LED units each including 7 LEDs 931 are assumed in LED module 630 and described as follows for illustration. A positive conductive line 934 and a negative conductive line 935 are to receive a driving signal, for supplying power to the LEDs 931. For example, positive conductive line 934 may be coupled to the filtering output terminal 521 of the filtering circuit 520 described above, and negative conductive line 935 coupled to the filtering output terminal 522 of the filtering circuit 520, to receive a filtered signal. For the convenience of illustration, all seven LEDs 931 of each of the three LED units are grouped as an LED set 932 in FIG. 32D. Thus, in this example, there are three LED sets 932 corresponding to the three LED units.

Positive conductive line 934 connects to the anode on the left side of the first or leftmost LED 931 of each of the three LED sets 932. Negative conductive line 935 connects to the cathode on the right side of the last or rightmost LED 931 of each of the three LED sets 932. In each LED set 932, of two consecutive LEDs 931 the LED 931 on the left has a cathode connected by a conductive part 939 to an anode of the LED 931 on the right. By such a layout, the LEDs 931 of each LED set 932 are connected in series.

In some embodiments, a conductive part 939 may be used to connect an anode and a cathode respectively of two consecutive LEDs 931. Negative conductive line 935 connects to the cathode of the last or rightmost LED 931 of each of the three LED sets 932. And positive conductive line 934 connects to the anode of the first or leftmost LED 931 of each of the three LED sets 932. Therefore, as shown in FIG. 32D, the length (and thus area) of the conductive part 939 is larger than that of the portion of negative conductive line 935 immediately connecting to a cathode, which length (and thus area) is then larger than that of the portion of positive conductive line 934 immediately connecting to an anode. For example, the length 938 of the conductive part 939 may be larger than the length 937 of the portion of negative conductive line 935 immediately connecting to a cathode of an LED 931, which length 937 is then larger than the length 936 of the portion of positive conductive line 934 immediately connecting to an anode of an LED 931. Such a layout structure improves heat dissipation of the LEDs 931 in LED module 630.

Positive conductive line 934 may include a lengthwise portion 934 a, and negative conductive line 935 may include a lengthwise portion 935 a, which are conducive to making the LED module have a positive “+” connective portion and a negative “−” connective portion at each of the two ends of the LED module, as shown in FIG. 32D. Such a layout structure allows for coupling any of other circuits of the power supply module of the LED lamp, including e.g. filtering circuit 520 and rectifying circuits 510 and 540, to the LED module through the positive connective portion 934 a and/or the negative connective portion 935 a at each or both ends of the LED lamp. Thus, in some example embodiments, the layout structure may increase the flexibility in arranging actual circuits in the LED lamp.

Further, the circuit layouts as shown in FIG. 32C and FIG. 32D may be implemented with a bendable circuit sheet or substrate, which may be called a flexible circuit board depending on its specifically-defined use. For example, the bendable circuit sheet may comprise one conductive layer where positive conductive line 834, positive lengthwise portion 834 a, negative conductive line 835, negative lengthwise portion 835 a, and conductive parts 839 shown in FIG. 32C, and positive conductive line 934, positive lengthwise portion 934 a, negative conductive line 935, negative lengthwise portion 935 a, and conductive parts 939 shown in FIG. 32D are formed by the method of etching.

FIG. 32E is a plan view of a circuit layout of the LED module according to another exemplary embodiment. The layout structures of the LED module in FIG. 32E and FIG. 32C each correspond to the same way of connecting LEDs 831 as that shown in FIG. 32B, but the layout structure in FIG. 32E comprises two conductive layers, instead of only one conductive layer for forming the circuit layout as shown in FIG. 32C. Referring to FIG. 32E, the main difference from the layout in FIG. 32C is that positive conductive line 834 and negative conductive line 835 have a lengthwise portion 834 a and a lengthwise portion 835 a, respectively, formed instead in a second conductive layer. The difference is elaborated as follows.

Referring to FIG. 32E, the bendable circuit sheet of the LED module comprises a first conductive layer 2 a and a second conductive layer 2 c electrically insulated from each other by a dielectric layer 2 b (not shown). Of the two conductive layers, positive conductive line 834, negative conductive line 835, and conductive parts 839 in FIG. 32E are formed in first conductive layer 2 a by the method of etching for electrically connecting the plurality of LED components 831 e.g. in a form of a mesh, whereas positive lengthwise portion 834 a and negative lengthwise portion 835 a are formed in second conductive layer 2 c by etching for electrically connecting to (the filtering output terminal of) the filtering circuit. Further, positive conductive line 834 and negative conductive line 835 in first conductive layer 2 a have via points 834 b and via points 835 b, respectively, for connecting to second conductive layer 2 c. And positive lengthwise portion 834 a and negative lengthwise portion 835 a in second conductive layer 2 c have via points 834 c and via points 835 c, respectively. Via points 834 b are positioned corresponding to via points 834 c, for connecting positive conductive line 834 and positive lengthwise portion 834 a. Via points 835 b are positioned corresponding to via points 835 c, for connecting negative conductive line 835 and negative lengthwise portion 835 a. In some embodiments, the two conductive layers may be connected by forming a hole connecting each via point 834 b and a corresponding via point 834 c, and forming a hole connecting each via point 835 b and a corresponding via point 835 c, with the holes extending through the two conductive layers and the dielectric layer in-between. And positive conductive line 834 and positive lengthwise portion 834 a can be electrically connected by welding metallic part(s) through the connecting hole(s), and negative conductive line 835 and negative lengthwise portion 835 a can be electrically connected by welding metallic part(s) through the connecting hole(s).

Similarly, the layout structure of the LED module in FIG. 32D may alternatively have positive lengthwise portion 934 a and negative lengthwise portion 935 a disposed in a second conductive layer, to constitute a two-layer layout structure.

In some embodiments, the thickness of the second conductive layer of a two-layer bendable circuit sheet is in some embodiments larger than that of the first conductive layer, in order to reduce the voltage drop or loss along each of the positive lengthwise portion and the negative lengthwise portion disposed in the second conductive layer. Compared to a one-layer bendable circuit sheet, since a positive lengthwise portion and a negative lengthwise portion are disposed in a second conductive layer in a two-layer bendable circuit sheet, the width (between two lengthwise sides) of the two-layer bendable circuit sheet is or can be reduced. On the same fixture or plate in a production process, the number of bendable circuit sheets each with a shorter width that can be laid together at most is larger than the number of bendable circuit sheets each with a longer width that can be laid together at most. Thus, in some exemplary embodiments, adopting a bendable circuit sheet with a shorter width can increase the efficiency of production of the LED module. And reliability in the production process, such as the accuracy of welding position when welding (materials on) the LED components, can also be improved, because a two-layer bendable circuit sheet can better maintain its shape.

As a variant of the above embodiments, a type of LED tube lamp is provided that has at least some of the electronic components of its power supply module disposed on a light strip of the LED tube lamp. For example, the technique of printed electronic circuit (PEC) can be used to print, insert, or embed at least some of the electronic components onto the light strip.

In one embodiment, all electronic components of the power supply module are disposed on the light strip. The production process may include or proceed with the following steps: preparation of the circuit substrate (e.g. preparation of a flexible printed circuit board); ink jet printing of metallic nano-ink; ink jet printing of active and passive components (as of the power supply module); drying/sintering; ink jet printing of interlayer bumps; spraying of insulating ink; ink jet printing of metallic nano-ink; ink jet printing of active and passive components (to sequentially form the included layers); spraying of surface bond pad(s); and spraying of solder resist against LED components.

In certain embodiments, if all electronic components of the power supply module are disposed on the light strip, electrical connection between terminal pins of the LED tube lamp and the light strip may be achieved by connecting the pins to conductive lines which are welded with ends of the light strip. In this case, another substrate for supporting the power supply module is not used, thereby allowing of an improved design or arrangement in the end cap(s) of the LED tube lamp. In some embodiments, (components of) the power supply module are disposed at two ends of the light strip, in order to reduce the impact of heat generated from the power supply module's operations on the LED components. Since no substrate other than the light strip is used to support the power supply module in this case, the total amount of welding or soldering can be reduced, improving the general reliability of the power supply module.

Another case is that some of all electronic components of the power supply module, such as some resistors and/or smaller size capacitors, are printed onto the light strip, and some bigger size components, such as some inductors and/or electrolytic capacitors, are disposed in the end cap(s). The production process of the light strip in this case may be the same as that described above. And in this case disposing some of all electronic components on the light strip is conducive to achieving a reasonable layout of the power supply module in the LED tube lamp, which may allow of an improved design in the end cap(s).

As a variant embodiment of the above, electronic components of the power supply module may be disposed on the light strip by a method of embedding or inserting, e.g. by embedding the components onto a bendable or flexible light strip. In some embodiments, this embedding may be realized by a method using copper-clad laminates (CCL) for forming a resistor or capacitor; a method using ink related to silkscreen printing; or a method of ink jet printing to embed passive components, wherein an ink jet printer is used to directly print inks to constitute passive components and related functionalities to intended positions on the light strip. Then through treatment by ultraviolet (UV) light or drying/sintering, the light strip is formed where passive components are embedded. The electronic components embedded onto the light strip include for example resistors, capacitors, and inductors. In other embodiments, active components also may be embedded. Through embedding some components onto the light strip, a reasonable layout of the power supply module can be achieved to allow of an improved design in the end cap(s), because the surface area on a printed circuit board used for carrying components of the power supply module is reduced or smaller, and as a result the size, weight, and thickness of the resulting printed circuit board for carrying components of the power supply module is also smaller or reduced. Also in this situation since welding points on the printed circuit board for welding resistors and/or capacitors if they were not to be disposed on the light strip are no longer used, the reliability of the power supply module is improved, in view of the fact that these welding points are most liable to (cause or incur) faults, malfunctions, or failures. Further, the length of conductive lines for connecting components on the printed circuit board is therefore also reduced, which allows of a more compact layout of components on the printed circuit board and thus improving the functionalities of these components.

Next, methods to produce embedded capacitors and resistors are explained as follows.

Usually, methods for manufacturing embedded capacitors employ or involve a concept called distributed or planar capacitance. The manufacturing process may include the following step(s). On a substrate of a copper layer a very thin insulation layer is applied or pressed, which is then generally disposed between a pair of layers including a power conductive layer and a ground layer. The very thin insulation layer makes the distance between the power conductive layer and the ground layer very short. A capacitance resulting from this structure can also be realized by a conventional technique of a plated-through hole. Basically, this step is used to create this structure comprising a big parallel-plate capacitor on a circuit substrate.

Of products of high electrical capacity, certain types of products employ distributed capacitances, and other types of products employ separate embedded capacitances. Through putting or adding a high dielectric-constant material such as barium titanate into the insulation layer, the high electrical capacity is achieved.

A usual method for manufacturing embedded resistors employ conductive or resistive adhesive. This may include, for example, a resin to which conductive carbon or graphite is added, which may be used as an additive or filler. The additive resin is silkscreen printed to an object location, and is then after treatment laminated inside the circuit board. The resulting resistor is connected to other electronic components through plated-through holes or microvias. Another method is called Ohmega-Ply, by which a two metallic layer structure of a copper layer and a thin nickel alloy layer constitutes a layer resistor relative to a substrate. Then through etching the copper layer and nickel alloy layer, different types of nickel alloy resistors with copper terminals can be formed. These types of resistor are each laminated inside the circuit board.

In an embodiment, conductive wires/lines are directly printed in a linear layout on an inner surface of the LED glass lamp tube, with LED components directly attached on the inner surface and electrically connected by the conductive wires. In some embodiments, the LED components in the form of chips are directly attached over the conductive wires on the inner surface, and connective points are at terminals of the wires for connecting the LED components and the power supply module. After being attached, the LED chips may have fluorescent powder applied or dropped thereon, for producing white light or light of other color by the operating LED tube lamp.

In some embodiments, luminous efficacy of the LED or LED component is 80 lm/W or above, and in some embodiments, luminous efficacy of the LED or LED component may be 120 lm/W or above. In certain embodiments, luminous efficacy of the LED or LED component may be 160 lm/W or above. White light emitted by an LED component may be produced by mixing fluorescent powder with the monochromatic light emitted by a monochromatic LED chip. The white light in its spectrum has major wavelength ranges of 430-460 nm and 550-560 nm, or major wavelength ranges of 430-460 nm, 540-560 nm, and 620-640 nm.

FIG. 33A is a block diagram of a power supply module in an LED lamp according to an exemplary embodiment. As shown in FIG. 33A, the power supply module of the LED lamp includes rectifying circuits 510 and 540, a filtering circuit 520, and a driving circuit 1530. In this embodiment, a driving circuit 1530 and an LED module 630 compose the LED lighting module 530. According to the above description in FIG. 29D, driving circuit 1530 in FIG. 33A comprises a DC-to-DC converter circuit, and is coupled to filtering output terminals 521 and 522 to receive a filtered signal and then perform power conversion for converting the filtered signal into a driving signal at driving output terminals 1521 and 1522. The LED module 630 is coupled to driving output terminals 1521 and 1522 to receive the driving signal for emitting light. In some embodiments, the current of LED module 630 is stabilized at an objective current value. Descriptions of this LED module 630 are the same as those provided above with reference to FIG. 32A to FIG. 32D.

LED lighting module 530 in embodiments of FIG. 33A, FIG. 33C, and FIG. 33E may comprise a driving circuit 1530 and an LED module 630. Therefore, the power supply module of the LED lamp in this embodiment can be used with a single-end power supply coupled to one end of the LED lamp, and can be used with a dual-end power supply coupled to two ends of the LED lamp. With a single-end power supply, examples of the LED lamp include an LED light bulb, a personal area light (PAL), etc.

FIG. 33B is a block diagram of the driving circuit according to an exemplary embodiment. Referring to FIG. 33B, the driving circuit includes a controller 1531, and a conversion circuit 1532 for power conversion based on a current source, for driving the LED module to emit light. Conversion circuit 1532 includes a switching circuit 1535 and an energy storage circuit 1538. And conversion circuit 1532 is coupled to filtering output terminals 521 and 522 to receive and then convert a filtered signal, under the control by controller 1531, into a driving signal at driving output terminals 1521 and 1522 for driving the LED module. Under the control by controller 1531, the driving signal output by conversion circuit 1532 comprises a steady current, making the LED module emitting steady light.

FIG. 33C is a schematic diagram of the driving circuit according to an exemplary embodiment. Referring to FIG. 33C, a driving circuit 1630 in this embodiment comprises a buck DC-to-DC converter circuit having a controller 1631 and a converter circuit. The converter circuit includes an inductor 1632, a diode 1633 for “freewheeling” of current, a capacitor 1634, and a switch 1635. Driving circuit 1630 is coupled to filtering output terminals 521 and 522 to receive and then convert a filtered signal into a driving signal for driving an LED module connected between driving output terminals 1521 and 1522.

In this embodiment, switch 1635 comprises a metal-oxide-semiconductor field-effect transistor (MOSFET) and has a first terminal coupled to the anode of freewheeling diode 1633, a second terminal coupled to filtering output terminal 522, and a control terminal coupled to controller 1631 used for controlling current conduction or cutoff between the first and second terminals of switch 1635. Driving output terminal 1521 is connected to filtering output terminal 521, and driving output terminal 1522 is connected to an end of inductor 1632, which has another end connected to the first terminal of switch 1635. Capacitor 1634 is coupled between driving output terminals 1521 and 1522, to stabilize the voltage between driving output terminals 1521 and 1522. Freewheeling diode 1633 has a cathode connected to driving output terminal 1521.

Next, a description follows as to an exemplary operation of driving circuit 1630.

Controller 1631 is configured for determining when to turn switch 1635 on (in a conducting state) or off (in a cutoff state), according to a current detection signal S535 and/or a current detection signal S531. For example, in some embodiments, controller 1631 is configured to control the duty cycle of switch 1635 being on and switch 1635 being off, in order to adjust the size or magnitude of the driving signal. Current detection signal S535 represents the magnitude of current through switch 1635. Current detection signal S531 represents the magnitude of current through the LED module coupled between driving output terminals 1521 and 1522. According to any of current detection signal S535 and current detection signal S531, controller 1631 can obtain information on the magnitude of power converted by the converter circuit. When switch 1635 is switched on, a current of a filtered signal is input through filtering output terminal 521, and then flows through capacitor 1634, driving output terminal 1521, the LED module, inductor 1632, and switch 1635, and then flows out from filtering output terminal 522. During this flowing of current, capacitor 1634 and inductor 1632 are performing storing of energy. On the other hand, when switch 1635 is switched off, capacitor 1634 and inductor 1632 perform releasing of stored energy by a current flowing from freewheeling capacitor 1633 to driving output terminal 1521 to make the LED module continuing to emit light.

In some embodiments, capacitor 1634 is an optional element, so it can be omitted and is thus depicted in a dotted line in FIG. 33C. In some application environments, the natural characteristic of an inductor to oppose instantaneous change in electric current passing through the inductor may be used to achieve the effect of stabilizing the current through the LED module, thus omitting capacitor 1634.

FIG. 33D is a schematic diagram of the driving circuit according to an exemplary embodiment. Referring to FIG. 33D, a driving circuit 1730 in this embodiment comprises a boost DC-to-DC converter circuit having a controller 1731 and a converter circuit. The converter circuit includes an inductor 1732, a diode 1733 for “freewheeling” of current, a capacitor 1734, and a switch 1735. Driving circuit 1730 is configured to receive and then convert a filtered signal from filtering output terminals 521 and 522 into a driving signal for driving an LED module coupled between driving output terminals 1521 and 1522.

Inductor 1732 has an end connected to filtering output terminal 521, and another end connected to the anode of freewheeling diode 1733 and a first terminal of switch 1735, which has a second terminal connected to filtering output terminal 522 and driving output terminal 1522. Freewheeling diode 1733 has a cathode connected to driving output terminal 1521. And capacitor 1734 is coupled between driving output terminals 1521 and 1522.

Controller 1731 is coupled to a control terminal of switch 1735, and is configured for determining when to turn switch 1735 on (in a conducting state) or off (in a cutoff state), according to a current detection signal S535 and/or a current detection signal S531. When switch 1735 is switched on, a current of a filtered signal is input through filtering output terminal 521, and then flows through inductor 1732 and switch 1735, and then flows out from filtering output terminal 522. During this flowing of current, the current through inductor 1732 increases with time, with inductor 1732 being in a state of storing energy, while capacitor 1734 enters a state of releasing energy, making the LED module continuing to emit light. On the other hand, when switch 1735 is switched off, inductor 1732 enters a state of releasing energy as the current through inductor 1732 decreases with time. In this state, the current through inductor 1732 then flows through freewheeling diode 1733, capacitor 1734, and the LED module, while capacitor 1734 enters a state of storing energy.

In some embodiments, capacitor 1734 is an optional element, so it can be omitted and is thus depicted in a dotted line in FIG. 33D. When capacitor 1734 is omitted and switch 1735 is switched on, the current of inductor 1732 does not flow through the LED module, making the LED module not emit light; but when switch 1735 is switched off, the current of inductor 1732 flows through freewheeling diode 1733 to reach the LED module, making the LED module emit light. Therefore, by controlling the time that the LED module emits light, and the magnitude of current through the LED module, the average luminance of the LED module can be stabilized to be above a defined value, thus also achieving the effect of emitting a steady light.

FIG. 33E is a schematic diagram of the driving circuit according to an exemplary embodiment. Referring to FIG. 33E, a driving circuit 1830 in this embodiment comprises a buck DC-to-DC converter circuit having a controller 1831 and a converter circuit. The converter circuit includes an inductor 1832, a diode 1833 for “freewheeling” of current, a capacitor 1834, and a switch 1835. Driving circuit 1830 is coupled to filtering output terminals 521 and 522 to receive and then convert a filtered signal into a driving signal for driving an LED module connected between driving output terminals 1521 and 1522.

Switch 1835 has a first terminal coupled to filtering output terminal 521, a second terminal coupled to the cathode of freewheeling diode 1833, and a control terminal coupled to controller 1831 to receive a control signal from controller 1831 for controlling current conduction or cutoff between the first and second terminals of switch 1835. The anode of freewheeling diode 1833 is connected to filtering output terminal 522 and driving output terminal 1522. Inductor 1832 has an end connected to the second terminal of switch 1835, and another end connected to driving output terminal 1521. Capacitor 1834 is coupled between driving output terminals 1521 and 1522, to stabilize the voltage between driving output terminals 1521 and 1522.

Controller 1831 is configured for controlling when to turn switch 1835 on (in a conducting state) or off (in a cutoff state), according to a current detection signal S535 and/or a current detection signal S531. When switch 1835 is switched on, a current of a filtered signal is input through filtering output terminal 521, and then flows through switch 1835, inductor 1832, and driving output terminals 1521 and 1522, and then flows out from filtering output terminal 522. During this flowing of current, the current through inductor 1832 and the voltage of capacitor 1834 both increase with time, so inductor 1832 and capacitor 1834 are in a state of storing energy. On the other hand, when switch 1835 is switched off, inductor 1832 is in a state of releasing energy and thus the current through it decreases with time. In this case, the current through inductor 1832 circulates through driving output terminals 1521 and 1522, freewheeling diode 1833, and back to inductor 1832.

In some embodiments, capacitor 1834 is an optional element, so it can be omitted and is thus depicted in a dotted line in FIG. 33E. When capacitor 1834 is omitted, no matter whether switch 1835 is turned on or off, the current through inductor 1832 will flow through driving output terminals 1521 and 1522 to drive the LED module to continue emitting light.

FIG. 33F is a schematic diagram of the driving circuit according to an exemplary embodiment. Referring to FIG. 33F, a driving circuit 1930 in this embodiment comprises a buck DC-to-DC converter circuit having a controller 1931 and a converter circuit. The converter circuit includes an inductor 1932, a diode 1933 for “freewheeling” of current, a capacitor 1934, and a switch 1935. Driving circuit 1930 is coupled to filtering output terminals 521 and 522 to receive and then convert a filtered signal into a driving signal for driving an LED module connected between driving output terminals 1521 and 1522.

Inductor 1932 has an end connected to filtering output terminal 521 and driving output terminal 1522, and another end connected to a first end of switch 1935. Switch 1935 has a second end connected to filtering output terminal 522, and a control terminal connected to controller 1931 to receive a control signal from controller 1931 for controlling current conduction or cutoff of switch 1935. Freewheeling diode 1933 has an anode coupled to a node connecting inductor 1932 and switch 1935, and a cathode coupled to driving output terminal 1521. Capacitor 1934 is coupled to driving output terminals 1521 and 1522, to stabilize the driving of the LED module coupled between driving output terminals 1521 and 1522.

Controller 1931 is configured for controlling when to turn switch 1935 on (in a conducting state) or off (in a cutoff state), according to a current detection signal S531 and/or a current detection signal S535. When switch 1935 is turned on, a current is input through filtering output terminal 521, and then flows through inductor 1932 and switch 1935, and then flows out from filtering output terminal 522. During this flowing of current, the current through inductor 1932 increases with time, so inductor 1932 is in a state of storing energy; but the voltage of capacitor 1934 decreases with time, so capacitor 1934 is in a state of releasing energy to keep the LED module continuing to emit light. On the other hand, when switch 1935 is turned off, inductor 1932 is in a state of releasing energy and its current decreases with time. In this case, the current through inductor 1932 circulates through freewheeling diode 1933, driving output terminals 1521 and 1522, and back to inductor 1932. During this circulation, capacitor 1934 is in a state of storing energy and its voltage increases with time.

In some embodiments, capacitor 1934 is an optional element, so it can be omitted and is thus depicted in a dotted line in FIG. 33F. When capacitor 1934 is omitted and switch 1935 is turned on, the current through inductor 1932 doesn't flow through driving output terminals 1521 and 1522, thereby making the LED module not emit light. On the other hand, when switch 1935 is turned off, the current through inductor 1932 flows through freewheeling diode 1933 and then the LED module to make the LED module emit light. Therefore, by controlling the time that the LED module emits light, and the magnitude of current through the LED module, the average luminance of the LED module can be stabilized to be above a defined value, thus also achieving the effect of emitting a steady light.

FIG. 33G is a block diagram of the driving circuit according to an exemplary embodiment. Referring to FIG. 33G, the driving circuit includes a controller 2631, and a conversion circuit 2632 for power conversion based on an adjustable current source, for driving the LED module to emit light. Conversion circuit 2632 includes a switching circuit 2635 and an energy storage circuit 2638. And conversion circuit 2632 is coupled to filtering output terminals 521 and 522 to receive and then convert a filtered signal, under the control by controller 2631, into a driving signal at driving output terminals 1521 and 1522 for driving the LED module. Controller 2631 is configured to receive a current detection signal S535 and/or a current detection signal S539, for controlling or stabilizing the driving signal output by conversion circuit 2632 to be above an objective current value. Current detection signal S535 represents the magnitude of current through switching circuit 2635. Current detection signal S539 represents the magnitude of current through energy storage circuit 2638, which current may be e.g. an inductor current in energy storage circuit 2638 or a current output at driving output terminal 1521. Any of current detection signal S535 and current detection signal S539 can represent the magnitude of current Iout provided by the driving circuit from driving output terminals 1521 and 1522 to the LED module. Controller 2631 is coupled to filtering output terminal 521 for setting the objective current value according to the voltage Vin at filtering output terminal 521. Therefore, the current Iout provided by the driving circuit or the objective current value can be adjusted corresponding to the magnitude of the voltage Vin of a filtered signal output by a filtering circuit.

In some embodiments, current detection signals S535 and S539 can be generated by measuring current through a resistor or induced by an inductor. For example, a current can be measured according to a voltage drop across a resistor in conversion circuit 2632 the current flows through, or which arises from a mutual induction between an inductor in conversion circuit 2632 and another inductor in its energy storage circuit 2638.

The above driving circuit structures are especially suitable for an application environment in which the external driving circuit for the LED tube lamp includes electronic ballast. An electronic ballast is equivalent to a current source whose output power is not constant. In an internal driving circuit as shown in each of FIG. 33C to FIG. 33F, power consumed by the internal driving circuit relates to or depends on the number of LEDs in the LED module, and could be regarded as constant. When the output power of the electronic ballast is higher than power consumed by the LED module driven by the driving circuit, the output voltage of the ballast will increase continually, causing the level of an AC driving signal received by the power supply module of the LED lamp to continually increase, so as to risk damaging the ballast and/or components of the power supply module due to their voltage ratings being exceeded. On the other hand, when the output power of the electronic ballast is lower than power consumed by the LED module driven by the driving circuit, the output voltage of the ballast and the level of the AC driving signal will decrease continually so that the LED tube lamp fail to normally operate.

The power needed for an LED lamp to work is already lower than that needed for a fluorescent lamp to work. If a conventional control mechanism of e.g. using a backlight module to control the LED luminance is used with a conventional driving system of e.g. a ballast, there may arise a mismatch or incompatibility between the output power of the external driving system and the power needed by the LED lamp. This mismatch may cause damage to the driving system and/or the LED lamp. To prevent this mismatch, using e.g. the power/current adjustment method described above in FIG. 33G enables the LED (tube) lamp to be better compatible with traditional fluorescent lighting system.

For example, capacitors of the driving circuit, such as capacitors 1634, 1734, 1834, and 1934 in FIG. 33C to FIG. 33F, in practical use may include two or more capacitors connected in parallel. Some or all capacitors of the driving circuit in the power supply module may be arranged on a first short circuit substrate of a short circuit board, while other components such as the rectifying circuit, filtering circuit, inductor(s) of the driving circuit, controller(s), switch(es), diodes, etc. may be arranged on a second short circuit substrate of a short circuit board. Since inductors, controllers, switches, etc. are electronic components with higher temperature, arranging some or all capacitors on a circuit substrate separate or away from the circuit substrate(s) of high-temperature components helps prevent the working life of capacitors (e.g., electrolytic capacitors) from being negatively affected by the high-temperature components, thus improving the reliability of the capacitors. By the above-mentioned circuit layout, the electronic components are easily electrically connected by welding metallic part(s) and further EMI is reduced.

In some embodiments, the driving circuit has power conversion efficiency of 80% or above. In certain embodiments, the driving circuit may have power conversion efficiency of 90% or above. And, in still other embodiments, the driving circuit may have power conversion efficiency of 92% or above. Therefore, without the driving circuit, luminous efficacy of the LED lamp according to some embodiments may be 120 lm/W or above, and may be 160 lm/W or above. On the other hand, with the driving circuit in combination with the LED component(s), luminous efficacy of the LED lamp may be, in some embodiments, 120 lm/W*90%=108 lm/W or above. In certain embodiments, luminous efficacy of the LED lamp may be 160 lm/W*92%=147.2 lm/W or above.

In view of the fact that the diffusion film or layer in an LED tube lamp has light transmittance of 85% or above, in some embodiments, luminous efficacy of the LED tube lamp may be 108 lm/W*85%=91.8 lm/W or above. In certain embodiments, luminous efficacy of the LED tube lamp may be 147.2 lm/W*85%=125.12 lm/W.

FIG. 34A is a block diagram showing a power supply module in an LED lamp according to an exemplary embodiment. Compared to FIG. 33A, the embodiment of FIG. 34A includes rectifying circuits 510 and 540, a filtering circuit 520, and a driving circuit 1530, and further includes an anti-flickering circuit 550 coupled between filtering circuit 520 and LED lighting module 530. In this embodiment, a driving circuit 1530 and an LED module 630 compose the LED lighting module 530.

Anti-flickering circuit 550 is coupled to filtering output terminals 521 and 522, to receive a filtered signal, and under specific circumstances to consume partial energy of the filtered signal so as to reduce (the incidence of) ripples of the filtered signal disrupting or interrupting the light emission of the LED lighting module 530. In general, filtering circuit 520 has such filtering components as resistor(s) and/or inductor(s), and/or parasitic capacitors and inductors, which may form resonant circuits. Upon breakoff or stop of an AC power signal, as when the power supply of the LED lamp is turned off by a user, the amplitude(s) of resonant signals in the resonant circuits will decrease with time. But LEDs in the LED module of the LED lamp are unidirectional conduction devices and may have a minimum conduction voltage for the LED module. When a resonant signal's trough value is lower than the minimum conduction voltage of the LED module, but its peak value is still higher than the minimum conduction voltage, the flickering phenomenon will occur in light emission of the LED module. In this example, anti-flickering circuit 550 operates by allowing a current matching a defined flickering current value of the LED component to flow through, consuming partial energy of the filtered signal, which may be higher than the energy difference of the resonant signal between its peak and trough values, so as to reduce the flickering phenomenon. In certain embodiments, anti-flickering circuit 550 may operate when the filtered signal's voltage approaches (and is still higher than) the minimum conduction voltage.

In some embodiments, anti-flickering circuit 550 may be used in the situation in which LED lighting module 530 doesn't include driving circuit 1530, for example, when LED module 630 of LED lighting module 530 is (directly) driven to emit light by a filtered signal from a filtering circuit. In this case, the light emission of LED module 630 will directly reflect variation in the filtered signal due to its ripples. In this situation, the introduction of anti-flickering circuit 550 will prevent the flickering phenomenon from occurring in the LED lamp upon the breakoff of power supply to the LED lamp.

FIG. 34B is a schematic diagram of the anti-flickering circuit according to an exemplary embodiment. Referring to FIG. 34B, anti-flickering circuit 650 includes at least a resistor, such as two resistors connected in series between filtering output terminals 521 and 522. In this embodiment, anti-flickering circuit 650 in use consumes partial energy of a filtered signal continually. When in normal operation of the LED lamp, this partial energy is far lower than the energy consumed by LED lighting module 530. But upon a breakoff or stop of the power supply, when the voltage level of the filtered signal decreases to approach the minimum conduction voltage of LED module 630, this partial energy is still consumed by anti-flickering circuit 650 in order to offset the impact of the resonant signals which may cause the flickering of light emission of LED module 630. In some embodiments, a current equal to or larger than an anti-flickering current level may be set to flow through anti-flickering circuit 650 when LED module 630 is supplied by the minimum conduction voltage, and then an equivalent anti-flickering resistance of anti-flickering circuit 650 can be determined based on the set current.

FIG. 35A is a block diagram showing a power supply module in an LED lamp according to an exemplary embodiment. Compared to FIG. 34A, the embodiment of FIG. 35A includes rectifying circuits 510 and 540, a filtering circuit 520, a driving circuit 1530, and an anti-flickering circuit 550, and further includes a protection circuit 560. In this embodiment, a driving circuit 1530 and an LED module 630 compose the LED lighting module 530. Protection circuit 560 is coupled to filtering output terminals 521 and 522, to detect the filtered signal from filtering circuit 520 for determining whether to enter a protection state. Upon entering a protection state, protection circuit 560 works to limit, restrain, or clamp down on the level of the filtered signal, preventing damaging of components in LED lighting module 530. And anti-flickering circuit 550 may be omitted and are thus depicted in a dotted line in FIG. 36A.

FIG. 35B is a schematic diagram of the protection circuit according to an exemplary embodiment. Referring to FIG. 35B, a protection circuit 660 includes a voltage clamping circuit, a voltage division circuit, capacitors 663 and 670, resistor 669, and a diode 672, for entering a protection state when a current and/or voltage of the LED module is/are or might be excessively high, thus preventing damaging of the LED module. The voltage clamping circuit includes a bidirectional triode thyristor (TRIAC) 661 and a DIAC or symmetrical trigger diode 662. The voltage division circuit includes bipolar junction transistors (BJT) 667 and 668 which respectively serve as first and second switches and resistors 664, 665, 666, and 671.

Bidirectional triode thyristor 661 has a first terminal connected to filtering output terminal 521, a second terminal connected to filtering output terminal 522, and a control terminal connected to a first terminal of symmetrical trigger diode 662, which has a second terminal connected to an end of capacitor 663, which has another end connected to filtering output terminal 522. Resistor 664 is in parallel to capacitor 663, and has an end connected to the second terminal of symmetrical trigger diode 662 and another end connected to filtering output terminal 522. Resistor 665 has an end connected to the second terminal of symmetrical trigger diode 662 and another end connected to the collector terminal of BJT 667, whose emitter terminal is connected to filtering output terminal 522. Resistor 666 has an end connected to the second terminal of symmetrical trigger diode 662 and another end connected to the collector terminal of BJT 668 and the base terminal of BJT 667. The emitter terminal of BJT 668 is connected to filtering output terminal 522. Resistor 669 has an end connected to the base terminal of BJT 668 and another end connected to an end of capacitor 670, which has another end connected to filtering output terminal 522. Resistor 671 has an end connected to the second terminal of symmetrical trigger diode 662 and another end connected to the cathode of diode 672, whose anode is connected to filtering output terminal 521.

According to some embodiments, the resistance of resistor 665 is smaller than that of resistor 666.

Next, an exemplary operation of protection circuit 660 in overcurrent protection is described as follows.

The node connecting resistor 669 and capacitor 670 is to receive a current detection signal S531, which represents the magnitude of current through the LED module. The other end of resistor 671 is a voltage terminal 521′. In this embodiment concerning overcurrent protection, voltage terminal 521′ may be coupled to a biasing voltage source, or be connected through diode 672 to filtering output terminal 521, as shown in FIG. 35B, to take a filtered signal as a biasing voltage source. If voltage terminal 521′ is coupled to an external biasing voltage source, diode 672 may be omitted, so it is depicted in a dotted line in FIG. 35B. The combination of resistor 669 and capacitor 670 can work to filter out high frequency components of the current detection signal S531, and then input the filtered current detection signal S531 to the base terminal of BJT 668 for controlling current conduction and cutoff of BJT 668. The filtering function of resistor 669 and capacitor 670 can prevent faulty operation of BJT 668 due to noise. In practical use, resistor 669 and capacitor 670 may be omitted, so they are each depicted in a dotted line in FIG. 35B. When they are omitted, current detection signal S531 is input directly to the base terminal of BJT 668.

When the LED lamp is operating normally and the current of the LED module is within a normal range, BJT 668 is in a cutoff state, and resistor 66 operates to pull up the base voltage of BJT 667, which therefore enters a conducting state. In this state, the electric potential at the second terminal of symmetrical trigger diode 662 is determined based on the voltage at voltage terminal 521′ of the biasing voltage source and voltage division ratios between resistor 671 and parallel-connected resistors 664 and 665. Since the resistance of resistor 665 is relatively small, voltage share for resistor 665 is smaller and the electric potential at the second terminal of symmetrical trigger diode 662 is therefore pulled down. Then, the electric potential at the control terminal of bidirectional triode thyristor 661 is in turn pulled down by symmetrical trigger diode 662, causing bidirectional triode thyristor 661 to enter a cutoff state, which cutoff state makes protection circuit 660 not being in a protection state.

When the current of the LED module exceeds an overcurrent value, the level of current detection signal S531 will increase to cause BJT 668 to enter a conducting state and then pull down the base voltage of BJT 667, which thereby enters a cutoff state. In this case, the electric potential at the second terminal of symmetrical trigger diode 662 is determined based on the voltage at voltage terminal 521′ of the biasing voltage source and voltage division ratios between resistor 671 and parallel-connected resistors 664 and 666. Since the resistance of resistor 666 is relatively high, voltage share for resistor 666 is larger and the electric potential at the second terminal of symmetrical trigger diode 662 is therefore higher. Then the electric potential at the control terminal of bidirectional triode thyristor 661 is in turn pulled up by symmetrical trigger diode 662, causing bidirectional triode thyristor 661 to enter a conducting state, which conducting state works to restrain or clamp down on the voltage between filtering output terminals 521 and 522 and thus makes protection circuit 660 being in a protection state.

In this embodiment, the voltage at voltage terminal 521′ of the biasing voltage source is determined based on the trigger voltage of bidirectional triode thyristor 661, and voltage division ratio between resistor 671 and parallel-connected resistors 664 and 665, or voltage division ratio between resistor 671 and parallel-connected resistors 664 and 666. Through voltage division between resistor 671 and parallel-connected resistors 664 and 665, the voltage from voltage terminal 521′ at symmetrical trigger diode 662 will be lower than the trigger voltage of bidirectional triode thyristor 661. Otherwise, through voltage division between resistor 671 and parallel-connected resistors 664 and 666, the voltage from voltage terminal 521′ at symmetrical trigger diode 662 will be higher than the trigger voltage of bidirectional triode thyristor 661. For example, in some embodiments, when the current of the LED module exceeds an overcurrent value, the voltage division circuit is adjusted to the voltage division ratio between resistor 671 and parallel-connected resistors 664 and 666, causing a higher portion of the voltage at voltage terminal 521′ to result at symmetrical trigger diode 662, achieving a hysteresis function. Specifically, BJTs 667 and 668 as switches are respectively connected in series to resistors 665 and 666 which determine the voltage division ratios. The voltage division circuit is configured to control turning on which one of BJTs 667 and 668 and leaving the other off for determining the relevant voltage division ratio, according to whether the current of the LED module exceeds an overcurrent value. And the clamping circuit determines whether to restrain or clamp down on the voltage of the LED module according to the applying voltage division ratio.

Next, an exemplary operation of protection circuit 660 in overvoltage protection is described as follows.

The node connecting resistor 669 and capacitor 670 is to receive a current detection signal S531, which represents the magnitude of current through the LED module. As described above, protection circuit 660 still works to provide overcurrent protection. The other end of resistor 671 is a voltage terminal 521′. In this embodiment concerning overvoltage protection, voltage terminal 521′ is coupled to the positive terminal of the LED module to detect the voltage of the LED module. Taking previously described embodiments for example, in embodiments of FIG. 32A and FIG. 32B, LED lighting module 530 doesn't include driving circuit 1530, and the voltage terminal 521′ would be coupled to filtering output terminal 521. Whereas in embodiments of FIG. 33A to FIG. 33G, LED lighting module 530 includes driving circuit 1530, and the voltage terminal 521′ would be coupled to driving output terminal 1521. In this embodiment, voltage division ratios between resistor 671 and parallel-connected resistors 664 and 665, and voltage division ratios between resistor 671 and parallel-connected resistors 664 and 666 will be adjusted according to the voltage at voltage terminal 521′, for example, the voltage at driving output terminal 1521 or filtering output terminal 521. Therefore, normal overcurrent protection can still be provided by protection circuit 660.

In some embodiments, when the LED lamp is operating normally, assuming overcurrent condition doesn't occur, the electric potential at the second terminal of symmetrical trigger diode 662 is determined based on the voltage at voltage terminal 521′ and voltage division ratios between resistor 671 and parallel-connected resistors 664 and 665, and is insufficient to trigger bidirectional triode thyristor 661. Then bidirectional triode thyristor 661 is in a cutoff state, making protection circuit 660 not being in a protection state. On the other hand, when the LED module is operating abnormally (e.g.: LED module is open-circuited) with the voltage at the positive terminal of the LED module exceeding an overvoltage value, the electric potential at the second terminal of symmetrical trigger diode 662 is sufficiently high to trigger bidirectional triode thyristor 661 when the voltage at the first terminal of symmetrical trigger diode 662 is larger than the trigger voltage of bidirectional triode thyristor 661. Then bidirectional triode thyristor 661 enters a conducting state, making protection circuit 660 being in a protection state to restrain or clamp down on the level of the filtered signal.

As described above, protection circuit 660 provides one or two of the functions of overcurrent protection and overvoltage protection.

In some embodiments, protection circuit 660 may further include a zener diode connected to resistor 664 in parallel, which zener diode is used to limit or restrain the voltage across resistor 664. The breakdown voltage of the zener diode is, in some embodiments, in the range of about 25˜50 volts. In certain embodiments, the breakdown voltage of the zener diode may be about 36 volts.

Further, a silicon controlled rectifier may be substituted for bidirectional triode thyristor 661 and a thyristor surge suppresser may be substituted for symmetrical trigger diode 662, without negatively affecting the protection functions. Using a silicon controlled rectifier instead of a bidirectional triode thyristor 661 has a lower voltage drop across itself in conduction than that across bidirectional triode thyristor 661 in conduction.

In one embodiment, values of the parameters of protection circuit 660 may be set as follows. Resistance of resistor 669 may be about 10 ohms. Capacitance of capacitor 670 may be about 1 nF. Capacitance of capacitor 633 may be about 10 nF. The (breakover) voltage of symmetrical trigger diode 662 may be in the range of about 26˜36 volts. Resistance of resistor 671 may be in the range of about 300 k˜600 k ohms, and may be, in some embodiments, about 540 k ohms. Resistance of resistor 666 is, in some embodiments, in the range of about 100 k˜300 k ohms, and in certain embodiments, may be about 220 k ohms. Resistance of resistor 665 is, in some embodiments, in the range of about 30 k˜100 k ohms, and in certain embodiments, may be about 40 k ohms. Resistance of resistor 664 is, in some embodiments, in the range of about 100 k˜300 k ohms, and in certain embodiments, may be about 220 k ohms.

FIG. 36A is a block diagram of a power supply module in an LED lamp according to an exemplary embodiment. Compared to FIG. 33A, the embodiment of FIG. 36A includes rectifying circuits 510 and 540, a filtering circuit 520, and a driving circuit 1530, and further includes a mode switching circuit 580. In this embodiment, a driving circuit 1530 and an LED module 630 compose the LED lighting module 530. Mode switching circuit 580 is coupled to at least one of filtering output terminals 521 and 522 and at least one of driving output terminals 1521 and 1522, for determining whether to perform a first driving mode or a second driving mode, as according to a frequency of the external driving signal. In the first driving mode, a filtered signal from filtering circuit 520 is input into driving circuit 1530, while in the second driving mode the filtered signal bypasses at least a component of driving circuit 1530, making driving circuit 1530 stop working in conducting the filtered signal, allowing the filtered signal to (directly) reach and drive LED module 630. The bypassed component(s) of driving circuit 1530 may include an inductor or a switch, which when bypassed makes driving circuit 1530 unable to transfer and/or convert power, and then stop working in conducting the filtered signal. If driving circuit 1530 includes a capacitor, the capacitor can still be used to filter out ripples of the filtered signal in order to stabilize the voltage across the LED module. When mode switching circuit 580 determines to perform the first driving mode, allowing the filtered signal to be input to driving circuit 1530, driving circuit 1530 then transforms the filtered signal into a driving signal for driving LED module 630 to emit light. On the other hand, when mode switching circuit 580 determines to perform the second driving mode, allowing the filtered signal to bypass driving circuit 1530 to reach LED module 630, the filtering circuit 520 becomes in effect a driving circuit for LED module 630. Then filtering circuit 520 provides the filtered signal as a driving signal for the LED module for driving the LED module to emit light.

In some embodiments, mode switching circuit 580 can determine whether to perform the first driving mode or the second driving mode based on a user's instruction or a detected signal received by the LED lamp through pins 501, 502, 503, and 504. In some embodiments, a mode determination circuit 590 is used to determine the first driving mode or the second driving mode based on a signal received by the LED lamp and so the mode switching circuit 580 can determine whether to perform the first driving mode or the second driving mode based on a determined result signal S580 or/and S585. With the mode switching circuit, the power supply module of the LED lamp can adapt to or perform one of appropriate driving modes corresponding to different application environments or driving systems, thus improving the compatibility of the LED lamp.

FIG. 36B is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36B, a mode switching circuit 680 includes a mode switch 681 suitable for use with the driving circuit 1630 in FIG. 33C. Referring to FIG. 36B and FIG. 33C, mode switch 681 has three terminals 683, 684, and 685, wherein terminal 683 is coupled to driving output terminal 1522, terminal 684 is coupled to filtering output terminal 522, and terminal 685 is coupled to the inductor 1632 in driving circuit 1630.

When mode switching circuit 680 determines to perform a first driving mode, mode switch 681 conducts current in a first conductive path through terminals 683 and 685 and a second conductive path through terminals 683 and 684 is in a cutoff state. In this case, driving output terminal 1522 is coupled to inductor 1632, and therefore driving circuit 1630 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 680 determines to perform a second driving mode, mode switch 681 conducts current in the second conductive path through terminals 683 and 684 and the first conductive path through terminals 683 and 685 is in a cutoff state. In this case, driving output terminal 1522 is coupled to filtering output terminal 522, and therefore driving circuit 1630 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing inductor 1632 and switch 1635 in driving circuit 1630.

FIG. 36C is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36C, a mode switching circuit 780 includes a mode switch 781 suitable for use with the driving circuit 1630 in FIG. 33C. Referring to FIG. 36C and FIG. 33C, mode switch 781 has three terminals 783, 784, and 785, wherein terminal 783 is coupled to filtering output terminal 522, terminal 784 is coupled to driving output terminal 1522, and terminal 785 is coupled to switch 1635 in driving circuit 1630.

When mode switching circuit 780 determines to perform a first driving mode, mode switch 781 conducts current in a first conductive path through terminals 783 and 785 and a second conductive path through terminals 783 and 784 is in a cutoff state. In this case, filtering output terminal 522 is coupled to switch 1635, and therefore driving circuit 1630 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 780 determines to perform a second driving mode, mode switch 781 conducts current in the second conductive path through terminals 783 and 784 and the first conductive path through terminals 783 and 785 is in a cutoff state. In this case, driving output terminal 1522 is coupled to filtering output terminal 522, and therefore driving circuit 1630 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing inductor 1632 and switch 1635 in driving circuit 1630.

FIG. 36D is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36D, a mode switching circuit 880 includes a mode switch 881 suitable for use with the driving circuit 1730 in FIG. 33D. Referring to FIG. 36D and FIG. 33D, mode switch 881 has three terminals 883, 884, and 885, wherein terminal 883 is coupled to filtering output terminal 521, terminal 884 is coupled to driving output terminal 1521, and terminal 885 is coupled to inductor 1732 in driving circuit 1730.

When mode switching circuit 880 determines to perform a first driving mode, mode switch 881 conducts current in a first conductive path through terminals 883 and 885 and a second conductive path through terminals 883 and 884 is in a cutoff state. In this case, filtering output terminal 521 is coupled to inductor 1732, and therefore driving circuit 1730 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 880 determines to perform a second driving mode, mode switch 881 conducts current in the second conductive path through terminals 883 and 884 and the first conductive path through terminals 883 and 885 is in a cutoff state. In this case, driving output terminal 1521 is coupled to filtering output terminal 521, and therefore driving circuit 1730 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing inductor 1732 and freewheeling diode 1733 in driving circuit 1730.

FIG. 36E is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36E, a mode switching circuit 980 includes a mode switch 981 suitable for use with the driving circuit 1730 in FIG. 33D. Referring to FIG. 36E and FIG. 33D, mode switch 981 has three terminals 983, 984, and 985, wherein terminal 983 is coupled to driving output terminal 1521, terminal 984 is coupled to filtering output terminal 521, and terminal 985 is coupled to the cathode of diode 1733 in driving circuit 1730.

When mode switching circuit 980 determines to perform a first driving mode, mode switch 981 conducts current in a first conductive path through terminals 983 and 985 and a second conductive path through terminals 983 and 984 is in a cutoff state. In this case, filtering output terminal 521 is coupled to the cathode of diode 1733, and therefore driving circuit 1730 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 980 determines to perform a second driving mode, mode switch 981 conducts current in the second conductive path through terminals 983 and 984 and the first conductive path through terminals 983 and 985 is in a cutoff state. In this case, driving output terminal 1521 is coupled to filtering output terminal 521, and therefore driving circuit 1730 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing inductor 1732 and freewheeling diode 1733 in driving circuit 1730.

FIG. 36F is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36F, a mode switching circuit 1680 includes a mode switch 1681 suitable for use with the driving circuit 1830 in FIG. 33E. Referring to FIG. 36F and FIG. 33E, mode switch 1681 has three terminals 1683, 1684, and 1685, wherein terminal 1683 is coupled to filtering output terminal 521, terminal 1684 is coupled to driving output terminal 1521, and terminal 1685 is coupled to switch 1835 in driving circuit 1830.

When mode switching circuit 1680 determines to perform a first driving mode, mode switch 1681 conducts current in a first conductive path through terminals 1683 and 1685 and a second conductive path through terminals 1683 and 1684 is in a cutoff state. In this case, filtering output terminal 521 is coupled to switch 1835, and therefore driving circuit 1830 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1680 determines to perform a second driving mode, mode switch 1681 conducts current in the second conductive path through terminals 1683 and 1684 and the first conductive path through terminals 1683 and 1685 is in a cutoff state. In this case, driving output terminal 1521 is coupled to filtering output terminal 521, and therefore driving circuit 1830 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing inductor 1832 and switch 1835 in driving circuit 1830.

FIG. 36G is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36G, a mode switching circuit 1780 includes a mode switch 1781 suitable for use with the driving circuit 1830 in FIG. 33E. Referring to FIG. 36G and FIG. 33E, mode switch 1781 has three terminals 1783, 1784, and 1785, wherein terminal 1783 is coupled to filtering output terminal 521, terminal 1784 is coupled to driving output terminal 1521, and terminal 1785 is coupled to inductor 1832 in driving circuit 1830.

When mode switching circuit 1780 determines to perform a first driving mode, mode switch 1781 conducts current in a first conductive path through terminals 1783 and 1785 and a second conductive path through terminals 1783 and 1784 is in a cutoff state. In this case, filtering output terminal 521 is coupled to inductor 1832, and therefore driving circuit 1830 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1780 determines to perform a second driving mode, mode switch 1781 conducts current in the second conductive path through terminals 1783 and 1784 and the first conductive path through terminals 1783 and 1785 is in a cutoff state. In this case, driving output terminal 1521 is coupled to filtering output terminal 521, and therefore driving circuit 1830 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing inductor 1832 and switch 1835 in driving circuit 1830.

FIG. 36H is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36H, a mode switching circuit 1880 includes mode switches 1881 and 1882 suitable for use with the driving circuit 1930 in FIG. 33F. Referring to FIG. 36H and FIG. 33F, mode switch 1881 has three terminals 1883, 1884, and 1885, wherein terminal 1883 is coupled to driving output terminal 1521, terminal 1884 is coupled to filtering output terminal 521, and terminal 1885 is coupled to freewheeling diode 1933 in driving circuit 1930. And mode switch 1882 has three terminals 1886, 1887, and 1888, wherein terminal 1886 is coupled to driving output terminal 1522, terminal 1887 is coupled to filtering output terminal 522, and terminal 1888 is coupled to filtering output terminal 521.

When mode switching circuit 1880 determines to perform a first driving mode, mode switch 1881 conducts current in a first conductive path through terminals 1883 and 1885 and a second conductive path through terminals 1883 and 1884 is in a cutoff state, and mode switch 1882 conducts current in a third conductive path through terminals 1886 and 1888 and a fourth conductive path through terminals 1886 and 1887 is in a cutoff state. In this case, driving output terminal 1521 is coupled to freewheeling diode 1933, and filtering output terminal 521 is coupled to driving output terminal 1522. Therefore driving circuit 1930 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal, output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1880 determines to perform a second driving mode, mode switch 1881 conducts current in the second conductive path through terminals 1883 and 1884 and the first conductive path through terminals 1883 and 1885 is in a cutoff state, and mode switch 1882 conducts current in the fourth conductive path through terminals 1886 and 1887 and the third conductive path through terminals 1886 and 1888 is in a cutoff state. In this case, driving output terminal 1521 is coupled to filtering output terminal 521, and filtering output terminal 522 is coupled to driving output terminal 1522. Therefore driving circuit 1930 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to drive output terminals 1521 and 1522 for driving the LED module, while bypassing freewheeling diode 1933 and switch 1935 in driving circuit 1930.

FIG. 36I is a schematic diagram of the mode switching circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36I, a mode switching circuit 1980 includes mode switches 1981 and 1982 suitable for use with the driving circuit 1930 in FIG. 33F. Referring to FIG. 36I and FIG. 33F, mode switch 1981 has three terminals 1983, 1984, and 1985, wherein terminal 1983 is coupled to filtering output terminal 522, terminal 1984 is coupled to driving output terminal 1522, and terminal 1985 is coupled to switch 1935 in driving circuit 1930. And mode switch 1982 has three terminals 1986, 1987, and 1988, wherein terminal 1986 is coupled to filtering output terminal 521, terminal 1987 is coupled to driving output terminal 1521, and terminal 1988 is coupled to driving output terminal 1522.

When mode switching circuit 1980 determines to perform a first driving mode, mode switch 1981 conducts current in a first conductive path through terminals 1983 and 1985 and a second conductive path through terminals 1983 and 1984 is in a cutoff state, and mode switch 1982 conducts current in a third conductive path through terminals 1986 and 1988 and a fourth conductive path through terminals 1986 and 1987 is in a cutoff state. In this case, driving output terminal 1522 is coupled to filtering output terminal 521, and filtering output terminal 522 is coupled to switch 1935. Therefore driving circuit 1930 is working normally, which working includes receiving a filtered signal from filtering output terminals 521 and 522 and then transforming the filtered signal into a driving signal that is output at driving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1980 determines to perform a second driving mode, mode switch 1981 conducts current in the second conductive path through terminals 1983 and 1984 and the first conductive path through terminals 1983 and 1985 is in a cutoff state, and mode switch 1982 conducts current in the fourth conductive path through terminals 1986 and 1987 and the third conductive path through terminals 1986 and 1988 is in a cutoff state. In this case, driving output terminal 1521 is coupled to filtering output terminal 521, and filtering output terminal 522 is coupled to driving output terminal 1522. Therefore driving circuit 1930 stops working, and a filtered signal is input through filtering output terminals 521 and 522 to driving output terminals 1521 and 1522 for driving the LED module, while bypassing freewheeling diode 1933 and switch 1935 in driving circuit 1930.

The mode switches in the above embodiments may each comprise, for example, a single-pole double-throw switch, or comprise two semiconductor switches (such as metal oxide semiconductor transistors), for switching a conductive path on to conduct current while leaving the other conductive path cutoff. Each of the two conductive paths provides a path for conducting the filtered signal, allowing the current of the filtered signal to flow through one of the two paths, thereby achieving the function of mode switching or selection. For example, with reference to FIG. 29A, and FIG. 29C in addition, when the lamp driving circuit 505 is not present and the LED tube lamp 500 is directly supplied by the AC power supply 508, the mode switching circuit may determine to perform a first driving mode in which the driving circuit (such as driving circuit 1530, 1630, 1730, 1830, or 1930) transforms the filtered signal into a driving signal of a level meeting a minimum level to properly drive the LED module to emit light. On the other hand, when the lamp driving circuit 505 is present, the mode switching circuit may determine to perform a second driving mode in which the filtered signal is (almost) directly used to drive the LED module to emit light; or alternatively the mode switching circuit may determine to perform the first driving mode to drive the LED module to emit light.

FIG. 36J is a schematic diagram of a mode determination circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36J, the mode determination circuit 690 comprises a symmetrical trigger diode 691 and a resistor 692, configured to detect a voltage level of an external driving signal. The symmetrical trigger diode 691 and the resistor 692 are connected in series. Namely, one end of the symmetrical trigger diode 691 is coupled to the first filtering output terminal 521, the other end thereof is coupled to one end of the resistor 692, and the other end of the resistor 692 is coupled to the second filtering output terminal 522. A connection node of the symmetrical trigger diode 691 and the resistor 692 generates a determined result signal S580 transmitted to a mode switching circuit. When an external driving signal is a signal with high frequency and high voltage, the determined result signal S580 is at a high voltage level to make the mode switching circuit determine to operate at the second driving mode. For example, when the lamp driving circuit 505 exists, as shown in FIG. 29A and FIG. 29C, the lamp driving circuit 505 converts the AC power signal of the AC power supply 508 into an AC driving signal with high frequency and high voltage that is transmitted into the LED tube lamp 500. At this time, the mode switch circuit determines to operate at the second driving mode and so the filtered signal, outputted by a first filtering output terminal 521 and a second filtering output terminal 522, directly drive the LED module 630 to emit light. When the external driving signal is a signal with low frequency and low voltage, the determined result signal S580 is at a low voltage level to make the mode switching circuit determine to operate at the first driving mode. For example, when the lamp driving circuit 505, as shown in FIG. 29A and FIG. 29C, does not exist, the AC power signal of the AC power supply 508 is directly transmitted into the LED tube lamp 500. At this time, the mode switch circuit determines to operate at the first driving mode and so the filtered signal, outputted by the first filtering output terminal 521 and the second filtering output terminal 522, is converted into an appropriate voltage level to drive the LED module 630 to emit light.

In some embodiments, a breakover voltage of the symmetrical trigger diode 691 is in a range of 400V˜1300V. In certain embodiments, the breakover voltage of the symmetrical trigger diode 691 may be in a range of 450V˜700V. In still other embodiments, the breakover voltage of the symmetrical trigger diode 691 may be in a range of 500V˜600V.

In some embodiments, the mode determination circuit 690 may include a resistor 693 and a switch 694. The resistor 693 and the switch 694 could be omitted based on the practice application, thus the resistor 693 and the switch 694 and a connection line thereof are depicted in a dotted line in FIG. 36J. The resistor 693 and the switch 694 are connected in series; namely one end of the resistor 693 is coupled to the first filtering output terminal 521, the other end is coupled to one end of the switch 694, and another end of the switch 694 is coupled to a second filtering output terminal 522. A control end of the switch 694 is coupled to the connection node of the symmetrical trigger diode 691 and the resistor 692 for receiving the determined result signal S580. Accordingly, a connection node of the resistor 693 and the switch 694 generates another determined result signal S585. The determined result signal S585 is an inverted signal of the determined result signal S580 and so they could be applied for a mode switch circuit having two mode switches, such as the mode switch circuit shown in FIG. 36H and FIG. 36.

FIG. 36K is a schematic diagram of a mode determination circuit in an LED lamp according to an exemplary embodiment. Referring to FIG. 36K, the mode determination circuit 790 includes a capacitor 791, resistors 791 and 793, and a switch 794. The capacitor 791 and the resistor 792 are connected in series as a frequency determination circuit 795 for detecting a frequency of an external driving signal. One end of the capacitor 792 is coupled to a first rectifying output terminal 511, the other end is coupled to one end of the resistor 791, and the other end of the resistor 791 is coupled to a second rectifying output terminal 512. The frequency determination circuit 795 generates the determined result signal S580 at a connection node of the resistor 791 and the capacitor 792. A voltage level of the determined result signal S580 is determined based on the frequency of the external driving signal. In some embodiment, the higher the frequency of the external driving signal is, the higher the voltage level of the determined result signal S580 is, and the lower the frequency of the external driving signal is, the lower the voltage level of the determined result signal S580 is. Hence, when the external driving signal is a higher frequency signal (e.g.: more than 20 KHz) and high voltage, the determined result signal S580 is at high voltage level to make the mode switch circuit determine to operate at second driving mode. When the external driving signal is a lower frequency signal and low voltage signal, the determined result signal S580 is at a low voltage level to make the mode switch circuit determine to operate at first driving mode. Similarly, in some embodiments, the mode determination circuit 790 may include a resistor 793 and a switch 794. The resistor 793 and the switch 794 are connected in series between the first filtering output terminal 521 and the second filtering output terminal 522, and a control end of the switch 794 is coupled to the frequency determination circuit 795 to receive the determined result signal S580. Accordingly, another determined result signal S585 is generated at a connection node of the resistor 793 and the switch 794 and is an inverted signal of the determined result signal S580. The determined result signals S580 and S585 may be applied to a mode switch circuit having two switches. The resistor 793 and the switch 794 could be omitted based on some applications and so are depicted in a dotted line.

FIG. 37A is a block diagram of a power supply module in an LED lamp according to an exemplary embodiment. Compared to FIG. 29D, the embodiment of FIG. 37A includes rectifying circuits 510 and 540, a filtering circuit 520, a driving circuit 1530, and a ballast-compatible circuit 1510. In this embodiment, a driving circuit 1530 and an LED module 630 compose the LED lighting module 530. The ballast-compatible circuit 1510 may be coupled between pin 501 and/or pin 502 and rectifying circuit 510. This embodiment is explained assuming the ballast-compatible circuit 1510 to be coupled between pin 501 and rectifying circuit 510. With reference to FIG. 29A and FIG. 29C in addition to FIG. 37A, lamp driving circuit 505 comprises a ballast configured to provide an AC driving signal to drive the LED lamp in this embodiment.

In an initial stage upon the activation of the driving system of lamp driving circuit 505, lamp driving circuit 505's ability to output relevant signal(s) has not risen to a standard state. However, in the initial stage the power supply module of the LED lamp instantly or rapidly receives or conducts the AC driving signal provided by lamp driving circuit 505, which initial conduction is likely to fail the starting of the LED lamp by lamp driving circuit 505 as lamp driving circuit 505 is initially loaded by the LED lamp in this stage. For example, internal components of lamp driving circuit 505 may retrieve power from a transformed output in lamp driving circuit 505 in order to maintain their operation upon the activation. In this case, the activation of lamp driving circuit 505 may end up failing as its output voltage could not normally rise to a minimal level in this initial stage; or the quality factor (Q) of a resonant circuit in lamp driving circuit 505 may vary as a result of the initial loading from the LED lamp, so as to cause the failure of the activation.

In this embodiment, in the initial stage upon activation, ballast-compatible circuit 1510 will be in an open-circuit state, preventing the energy of the AC driving signal from reaching the LED module. After a defined delay upon the AC driving signal as an external driving signal being input to the LED tube lamp, ballast-compatible circuit 1510 switches from a cutoff state during the delay to a conducting state, allowing the energy of the AC driving signal to start to reach the LED module. By means of the delayed conduction of ballast-compatible circuit 1510, operation of the LED lamp simulates the lamp-starting characteristics of a fluorescent lamp. For example, internal gases of the fluorescent lamp will discharge for light emission after a delay upon activation of a driving power supply. Therefore, ballast-compatible circuit 1510 further improves the compatibility of the LED lamp with lamp driving circuits 505, such as, for example, an electronic ballast.

FIG. 37B is a block diagram of a power supply module in an LED lamp according to an exemplary embodiment. Compared to FIG. 37A, ballast-compatible circuit 1510 in the embodiment of FIG. 37B is coupled between pin 503 and/or pin 504 and rectifying circuit 540. As explained regarding ballast-compatible circuit 1510 in FIG. 37A, ballast-compatible circuit 1510 in FIG. 37B performs the function of delaying the starting of the LED lamp, or causing the input of the AC driving signal to be delayed for a predefined time, in order to prevent the failure of starting by lamp driving circuits 505 such as an electronic ballast.

FIG. 37C is a block diagram of a power supply module in an LED lamp according to an exemplary embodiment. Compared to the embodiment of FIG. 37A, ballast-compatible circuit 1510 in the embodiment of FIG. 37C is coupled between rectifying circuit 540 and filtering circuit 520. Since rectifying circuit 540 also doesn't include components such as capacitors or inductors, the function of ballast-compatible circuit 1510 in the embodiment of FIG. 37C will not be affected.

FIG. 37D is a block diagram of a power supply module in an LED lamp according to an exemplary embodiment. Compared to the embodiment of FIG. 37A, ballast-compatible circuit 1510 in the embodiment of FIG. 37D is coupled between rectifying circuit 510 and filtering circuit 520. Similarly, since rectifying circuit 510 doesn't include components such as capacitors or inductors, the function of ballast-compatible circuit 1510 in the embodiment of FIG. 37D will not be affected.

FIG. 37E is a schematic diagram of the ballast-compatible circuit according to an exemplary embodiment. Referring to FIG. 37E, a ballast-compatible circuit 1610 has an initial state in which an equivalent open-circuit is obtained at ballast-compatible circuit input and output terminals 1611 and 1621. Upon receiving an input signal at ballast-compatible circuit input terminal 1611, a delay will pass until a current conduction occurs through and between ballast-compatible circuit input and output terminals 1611 and 1621, transmitting the input signal to ballast-compatible circuit output terminal 1621.

Ballast-compatible circuit 1610 includes a diode 1612, resistors 1613, 1615, 1618, 1620, and 1622, a bidirectional triode thyristor (TRIAC) 1614, a DIAC or symmetrical trigger diode 1617, a capacitor 1619, and ballast-compatible circuit input and output terminals 1611 and 1621. In some embodiments, the resistance of resistor 1613 may be large enough that, when bidirectional triode thyristor 1614 is cutoff in an open-circuit state, an equivalent open-circuit is obtained at ballast-compatible circuit input and output terminals 1611 and 1621.

Bidirectional triode thyristor 1614 is coupled between ballast-compatible circuit input and output terminals 1611 and 1621, and resistor 1613 is also coupled between ballast-compatible circuit input and output terminals 1611 and 1621 and in parallel to bidirectional triode thyristor 1614. Diode 1612, resistors 1620 and 1622, and capacitor 1619 are series-connected in sequence between ballast-compatible circuit input and output terminals 1611 and 1621, and are connected in parallel to bidirectional triode thyristor 1614. Diode 1612 has an anode connected to bidirectional triode thyristor 1614, and has a cathode connected to an end of resistor 1620. Bidirectional triode thyristor 1614 has a control terminal connected to a terminal of symmetrical trigger diode 1617, which has another terminal connected to an end of resistor 1618, which has another end connected to a node connecting capacitor 1619 and resistor 1622. Resistor 1615 is connected between the control terminal of bidirectional triode thyristor 1614 and a node connecting resistor 1613 and capacitor 1619. In some embodiments, the resistors 1615, 1618 and 1620 could be omitted, and so are depicted in a dotted line. When the resistor is emitted, the symmetrical trigger diode 1617 is directly connected to the connection node of the capacitor 1619 and the resistor 1622. When the resistor 1620 is omitted, the cathode of the diode 1612 is directly connected to the resistor 1622.

When an AC driving signal (such as a high-frequency high-voltage AC signal output by an electronic ballast) is initially input to ballast-compatible circuit input terminal 1611, bidirectional triode thyristor 1614 will be in an open-circuit state, not allowing the AC driving signal to pass through and the LED lamp is therefore also in an open-circuit state. In this state, the AC driving signal is charging capacitor 1619 through diode 1612 and resistors 1620 and 1622, gradually increasing the voltage of capacitor 1619. Upon continually charging for a period of time, the voltage of capacitor 1619 increases to be above the trigger voltage value of symmetrical trigger diode 1617 so that symmetrical trigger diode 1617 is turned on in a conducting state. Then the conducting symmetrical trigger diode 1617 will in turn trigger bidirectional triode thyristor 1614 on in a conducting state. In this situation, the conducting bidirectional triode thyristor 1614 electrically connects ballast-compatible circuit input and output terminals 1611 and 1621, allowing the AC driving signal to flow through ballast-compatible circuit input and output terminals 1611 and 1621, thus starting the operation of the power supply module of the LED lamp. In this case the energy stored by capacitor 1619 will maintain the conducting state of bidirectional triode thyristor 1614, to prevent the AC variation of the AC driving signal from causing bidirectional triode thyristor 1614 and therefore ballast-compatible circuit 1610 to be cutoff again, or to prevent the bidirectional triode thyristor 1614 alternating or switching between its conducting and cutoff states.

When the ballast-compatible circuit 1610 is applied to the circuit shown in FIG. 57C, the diode 1612 could be omitted due to that the ballast-compatible circuit 1610 receives a rectified signal by the rectifying unit or the rectifying circuit. In some embodiments, the bidirectional triode thyristor 1614 could be replaced by a Silicon Controlled Rectifier (SCR) and the symmetrical trigger diode 1617 could be replaced by a thyristor surge suppresser without affecting the protection function of the protection circuit. In some embodiments, the conduction voltage can be lowered by using SCR.

In general, within hundreds of milliseconds upon activation of a lamp driving circuit 505, such as an electronic ballast, the output voltage of the ballast may have risen above a certain voltage value as the output voltage hasn't been adversely affected by the initial loading from the LED lamp. In some embodiments, some instant-start ballasts output AC voltage at a substantially constant value for a short period of time after being started, such as 0.01 seconds. During this period, the voltage value may remain below 300 volts and then be raised. If a loading exists at the output during this period, it may be that the instant-start ballast cannot raise the voltage value of AC signal to a normal operation voltage value; especially when an input power source of the instant-start ballast is a 120 volts or lower commercial power. A detection mechanism to detect whether lighting of a fluorescent lamp is achieved may be disposed in lamp driving circuits 505 such as an electronic ballast. In this detection mechanism, if a fluorescent lamp fails to be lit up for a defined period of time, an abnormal state of the fluorescent lamp is detected, causing the fluorescent lamp to enter a protection state. In view of these facts, in certain embodiments, the delay provided by ballast-compatible circuit 1610 until conduction of ballast-compatible circuit 1610 and then the LED lamp may be longer than 0.1 seconds. In some embodiments, luminous efficacy of the LED or LED component may be in the range of about 0.1˜3 seconds.

In some embodiments, an additional capacitor 1623 may be coupled in parallel to resistor 1622. Capacitor 1623 works to reflect or support instantaneous change in the voltage between ballast-compatible circuit input and output terminals 1611 and 1621, and will not affect the function of delayed conduction performed by ballast-compatible circuit 1610.

FIG. 37G is a schematic diagram of the ballast-compatible circuit according to another exemplary embodiment. Referring to FIG. 37G, a ballast-compatible circuit 1710 has an initial state in which an equivalent open-circuit is obtained at ballast-compatible circuit input and output terminals 1711 and 1721. Upon receiving an input signal at ballast-compatible circuit input terminal 1711, ballast-compatible circuit 1710 will be in a cutoff state when the level of the input external driving signal is below a defined value corresponding to a conduction delay of ballast-compatible circuit 1710; and ballast-compatible circuit 1710 will enter a conducting state upon the level of the input external driving signal reaching the defined value, thus transmitting the input signal to ballast-compatible circuit output terminal 1721. In certain embodiments, the defined value may be equal to or more than 400 volts.

Ballast-compatible circuit 1710 includes a bidirectional triode thyristor (TRIAC) 1712, a DIAC or symmetrical trigger diode 1713, resistors 1714, 1716, and 1717, and a capacitor 1715. Bidirectional triode thyristor 1712 has a first terminal connected to ballast-compatible circuit input terminal 1711; a control terminal connected to a terminal of symmetrical trigger diode 1713 and an end of resistor 1714; and a second terminal connected to another end of resistor 1714. Capacitor 1715 has an end connected to another terminal of symmetrical trigger diode 1713, and has another end connected to the second terminal of bidirectional triode thyristor 1712. Resistor 1717 is in parallel connection with capacitor 1715, and is therefore also connected to said another terminal of symmetrical trigger diode 1713 and the second terminal of bidirectional triode thyristor 1712. And resistor 1716 has an end connected to the node connecting capacitor 1715 and symmetrical trigger diode 1713, and has another end connected to ballast-compatible circuit output terminal 1721.

When an AC driving signal (such as a high-frequency high-voltage AC signal output by an electronic ballast) is initially input to ballast-compatible circuit input terminal 1711, bidirectional triode thyristor 1712 will be in an open-circuit state, not allowing the AC driving signal to pass through and the LED lamp is therefore also in an open-circuit state. The input of the AC driving signal causes a potential difference between ballast-compatible circuit input terminal 1711 and ballast-compatible circuit output terminal 1721. When the AC driving signal increases with time to eventually reach a sufficient amplitude (which is a defined level after the delay) after a period of time, the signal level at ballast-compatible circuit output terminal 1721 has a reflected voltage at the control terminal of bidirectional triode thyristor 1712 after passing through resistor 1716, parallel-connected capacitor 1715 and resistor 1717, and resistor 1714, wherein the reflected voltage then triggers bidirectional triode thyristor 1712 into a conducting state. This conducting state makes ballast-compatible circuit 1710 entering a conducting state which causes the LED lamp to operate normally. Upon bidirectional triode thyristor 1712 conducting, a current flows through resistor 1716 and then charges capacitor 1715 to store a specific voltage on capacitor 1715. In this case, the energy stored by capacitor 1715 will maintain the conducting state of bidirectional triode thyristor 1712, to prevent the AC variation of the AC driving signal from causing bidirectional triode thyristor 1712 and therefore ballast-compatible circuit 1710 to be cutoff again, or to prevent the situation of bidirectional triode thyristor 1712 alternating or switching between its conducting and cutoff states.

FIG. 37F is a block diagram of a power supply system for an LED lamp according to an exemplary embodiment. Compared to the embodiment of FIG. 29C, lamp driving circuit 505 in the embodiment of FIG. 37F drives a plurality of LED tube lamps 500 connected in series, wherein a ballast-compatible circuit 1610 is disposed in each of the LED tube lamps 500. For the convenience of illustration, two series-connected LED tube lamps 500 are assumed for example and explained as follows.

Because the two ballast-compatible circuits 1610 respectively of the two LED tube lamps 500 can actually have different delays until conduction of the LED tube lamps 500, due to various factors such as errors occurring in production processes of some components, the actual timing of conduction of each of the ballast-compatible circuits 1610 is different. Upon activation of a lamp driving circuit 505, the voltage of the AC driving signal provided by lamp driving circuit 505 will be shared out by the two LED tube lamps 500 roughly equally. Subsequently when only one of the two LED tube lamps 500 first enters a conducting state, the voltage of the AC driving signal then will be borne mostly or entirely by the other LED tube lamp 500. This situation will cause the voltage across the ballast-compatible circuits 1610 in the other LED tube lamp 500 that's not conducting to increase or be doubled, meaning the voltage between ballast-compatible circuit input and output terminals 1611 and 1621 might be doubled. In view of this, if capacitor 1623 is included, the voltage division effect between capacitors 1619 and 1623 will increase the voltage of capacitor 1619, making symmetrical trigger diode 1617 triggering bidirectional triode thyristor 1614 into a conducting state, thus causing the two ballast-compatible circuits 1610, respectively of the two LED tube lamps 500, to become conducting almost at the same time. Therefore, where one of the two ballast-compatible circuits 1610 respectively of the two series-connected LED tube lamps 500 that is first conducting has its bidirectional triode thyristor 1614 suddenly cutoff as having insufficient current passing through due to the discrepancy between the delays provided by the two ballast-compatible circuits 1610 until their respective conductions, by introducing capacitor 1623, the situation can be avoided. Therefore, using each ballast-compatible circuit 1610 with capacitor 1623 further improves the compatibility of the series-connected LED tube lamps with each of lamp driving circuits 505 such as an electronic ballast.

In practical use, a range of the capacitance of capacitor 1623 is about 10 pF to about 1 nF. In some embodiments, the capacitance of capacitor 1623 may be in the range of about 10 pF to about 100 pF. In certain embodiments, the capacitance of capacitor 1623 may be about 47 pF.

In some embodiments, diode 1612 is used or configured to rectify the signal for charging capacitor 1619. Therefore, with reference to FIG. 38D and FIG. 38E, in the case when ballast-compatible circuit 1610 is arranged following a rectifying unit or circuit, diode 1612 may be omitted. Thus diode 1612 is depicted in a dotted line in FIG. 37E. FIG. 37H illustrates the ballast-compatible circuit according to an exemplary embodiment. Referring to FIG. 37H, a ballast-compatible circuit 1810 includes a housing 1812, a metallic electrode 1813, a bimetallic strip 1814, and a heating filament 1816. Metallic electrode 1813 and heating filament 1816 protrude from the housing 1812, so that they each have a portion inside the housing 1812 and a portion outside of the housing 1812. Metallic electrode 1813's outside portion has a ballast-compatible circuit input terminal 1811, and heating filament 1816's outside portion has a ballast-compatible circuit output terminal 1821. Housing 1812 is hermetic or tightly sealed and contains inertial gas 1815 such as helium gas. Bimetallic strip 1814 is inside housing 1812 and is physically and electrically connected to the portion of heating filament 1816 that is inside the housing 1812. In addition, there is a spacing between bimetallic strip 1814 and metallic electrode 1813, so that ballast-compatible circuit input terminal 1811 and ballast-compatible circuit output terminal 1821 are not electrically connected in the initial state of ballast-compatible circuit 1810. Bimetallic strip 1814 may include two metallic strips with different temperature coefficients, wherein the metallic strip closer to metallic electrode 1813 has a smaller temperature coefficient, and the metallic strip more away from metallic electrode 1813 has a larger temperature coefficient.

When an AC driving signal (such as a high-frequency high-voltage AC signal output by an electronic ballast) is initially input at ballast-compatible circuit input terminal 1811 and ballast-compatible circuit output terminal 1821, a potential difference between metallic electrode 1813 and heating filament 1816 is formed. When the potential difference increases enough to cause electric arc or arc discharge through inertial gas 1815, e.g., when the AC driving signal increases with time to eventually reach the defined level after a delay, inertial gas 1815 is then heated to cause bimetallic strip 1814 to swell toward metallic electrode 1813 (e.g., in the direction of the broken-line arrow in FIG. 37H), with this swelling eventually causing bimetallic strip 1814 to bear against metallic electrode 1813, forming the physical and electrical connections between them. In some embodiments, the defined value is equal to or more than 400 volts. In this situation, there is electrical conduction between ballast-compatible circuit input terminal 1811 and ballast-compatible circuit output terminal 1821. Then the AC driving signal flows through and thus heats heating filament 1816. In this heating process, heating filament 1816 allows a current to flow through when electrical conduction exists between metallic electrode 1813 and bimetallic strip 1814, causing the temperature of bimetallic strip 1814 to be above a defined conduction temperature. As a result, since the respective temperature of the two metallic strips of bimetallic strip 1814 with different temperature coefficients are maintained above the defined conduction temperature, bimetallic strip 1814 will bend against or toward metallic electrode 1813, thus maintaining or supporting the physical joining or connection between bimetallic strip 1814 and metallic electrode 1813.

Therefore, upon receiving an input signal at ballast-compatible circuit input and output terminals 1811 and 1821, a delay will pass until an electrical/current conduction occurs through and between ballast-compatible circuit input and output terminals 1811 and 1821.

Therefore, an exemplary ballast-compatible circuit such as described herein may be coupled between any pin and any rectifying circuit described above, wherein the ballast-compatible circuit will be in a cutoff state in a defined delay upon an external driving signal being input to the LED tube lamp, and will enter a conducting state after the delay. Otherwise, the ballast-compatible circuit will be in a cutoff state when the level of the input external driving signal is below a defined value corresponding to a conduction delay of the ballast-compatible circuit; and ballast-compatible circuit will enter a conducting state upon the level of the input external driving signal reaching the defined value. Accordingly, the compatibility of the LED tube lamp described herein with lamp driving circuits 505 such as an electronic ballast is further improved by using such a ballast-compatible circuit.

FIG. 37I is a schematic diagram of a ballast-compatible circuit according to some exemplary embodiments. Referring to FIG. 37I, the ballast-compatible circuit 1910 comprises resistors 1913, 1916 and 1917, a capacitor 1914, a control circuit 1918, and a switch 1919. One end of the resistor 1913 is coupled to a first rectifying output terminal 511, the other end is coupled to one end of the capacitor 1914, and the other end of the capacitor 1914 is coupled to a second rectifying output terminal 512. A connection node of the resistor 1913 and the capacitor 1914 is coupled to the control circuit 1918 to provide power to the control circuit 1918 for operation. The resistors 1916 and 1917 are connected in series between the first rectifying output terminal 511 and the second rectifying output terminal 512, and may generate a detection signal indicative of an external AC signal based on a voltage level of a rectified signal to the control circuit 1918. A control end of the switch 1919 is coupled to the control circuit 1918, and is turned on/off based on the control of the control circuit 1918. Two ends of the switch 1919 are coupled to ballast-compatible circuit terminals 1911 and 1921.

When the control circuit 1918 determines that the voltage level of the detection signal, generated by the resistors 1916 and 1917, is lower than a high determination level, the control circuit 1918 cuts the switch 1919 off. When the electronic ballast has just started, the voltage level of the output AC signal is not enough high and so the voltage level of detection signal is lower than the high determination level, the control circuit 1918 controls the switch 1919 on an open-circuit state. At this moment, the LED is open-circuited and stops operating. When the voltage level of the output AC signal raises to reach a sufficient amplitude (which is a defined level) in a time period, the voltage level of the detection signal is cyclically higher than the high determination level, the control circuit 1918 controls the switch 1919 to keep on a conduction state, and so the LED operates normally.

When an electronic ballast is applied, a level of an AC signal generated by the electronic ballast may range from about 200 to about 300 volts during the starting period (shorter than 100 ms, and usually range from about 20 to about 30 ms), and then the electronic ballast enters a normal state and the level of the AC signal is raised above the 300 volts. In some embodiments, a resistance of the resistor 1916 may range from about 200K to about 500K ohms. In certain embodiments, the resistance of the resistor 1916 may range from about 300K to about 400K ohms, and a resistance of the resistor 1917 may range from about 0.5K to about 4 Kohms. In still other embodiments, resistance of the resistor 1916 may range from about 1.0K to 3K ohms. The high determination level may range from 0.9 to 1.25 volts. In some embodiments, the high determination level may be about 1.0 volts.

In some embodiments, the ballast-compatible circuit could be applicable to detect the inductive ballast. The characteristic of the inductive ballast is zero-cross. When the inductive ballast is applied, the level of the detection signal generated by the resistors 1916 and 1917 is lower than a low determination level during the starting period powered by the commercial power, the control circuit 1918 controls the switch 1919 to keep on the conduction state and the LED tube lamp operates normally. In some embodiments, the low determination level is lower than 0.2 volts. In certain embodiments, the low determination level may be lower than 0.1 volts.

For example, during the starting period, if the detection signal is higher than the low determination level and lower than the high determination level (the high determination level is higher than the low determination level, the control circuit 1918 controls the switch 1919 to be cut off. On the other hand, when the detection signal is lower than the low determination level or higher than the high determination level, the control circuit 1918 controls the switch 1919 to be conducted continuously. Hence, the LED tube lamp using the ballast-compatible circuit can normally operate to light regardless of that the electronic ballast or the inductive ballast is applied

The resistors 1916 and 1917 is used to detect the level of the external AC signal, and in practice applications, a frequency detection circuit may use to replace the voltage detection circuit of the resistors 1916 and 1917. In general, the output signal of the electronic ballast has a frequency higher than 20 KHz, and that of the inductive ballast is lower than 400 Hz. By setting an appropriate frequency value, the frequency detection circuit could properly determine that an electronic ballast or an inductive ballast is applied, and so make the LED tube lamp operate normally to emit light.

FIG. 38A is a block diagram of a power supply module in an LED tube lamp according to an exemplary embodiment. Compared to that shown in FIG. 29D, the present embodiment comprises the rectifying circuits 510 and 540, the filtering circuit 520, and the driving circuit 1530, and further comprises two filament-simulating circuits 1560. In this embodiment, a driving circuit 1530 and an LED module 630 compose the LED lighting module 530. The filament-simulating circuits 1560 are respectively coupled between the pins 501 and 502 and coupled between the pins 503 and 504, for improving a compatibility with a lamp driving circuit having filament detection function, e.g.: program-start ballast.

In an initial stage upon the lamp driving circuit having filament detection function being activated, the lamp driving circuit will determine whether the filaments of the lamp operate normally or are in an abnormal condition of short-circuit or open-circuit. When determining the abnormal condition of the filaments, the lamp driving circuit stops operating and enters a protection state. In order to avoid that the lamp driving circuit erroneously determining the LED tube lamp to be abnormal due to the LED tube lamp having no filament, the two filament-simulating circuits 1560 simulate the operation of actual filaments of a fluorescent tube to have the lamp driving circuit enter into a normal state to start the LED lamp normally.

FIG. 38B is a schematic diagram of a filament-simulating circuit according to an exemplary embodiment. The filament-simulating circuit comprises a capacitor 1663 and a resistor 1665 connected in parallel, and two ends of the capacitor 1663 and two ends of the resistor 1665 are re respectively coupled to filament simulating terminals 1661 and 1662. Referring to FIG. 38A, the filament simulating terminals 1661 and 1662 of the two filament simulating 1660 are respectively coupled to the pins 501 and 502 and the pins 503 and 504. During the filament detection process, the lamp driving circuit outputs a detection signal to detect the state of the filaments. The detection signal passes the capacitor 1663 and the resistor 1665 and so the lamp driving circuit determines that the filaments of the LED lamp are normal.

In addition, a capacitance value of the capacitor 1663 is low and so a capacitive reactance (equivalent impedance) of the capacitor 1663 is far lower than an impedance of the resistor 1665 due to the lamp driving circuit outputting a high-frequency alternative current (AC) signal to drive LED lamp. Therefore, the filament-simulating circuit 1660 consumes fairly low power when the LED lamp operates normally, and so it almost does not affect the luminous efficiency of the LED lamp.

FIG. 38C is a schematic diagram of a filament-simulating circuit according to another exemplary embodiment. A filament-simulating circuit 1760 comprises capacitors 1763 and 1764, and the resistors 1765 and 1766. The capacitors 1763 and 1764 are connected in series and coupled between the filament simulating terminals 1661 and 1662. The resistors 1765 and 1766 are connected in series and coupled between the filament simulating terminals 1661 and 1662. Furthermore, the connection node of capacitors 1763 and 1764 is coupled to that of the resistors 1765 and 1766. Referring to FIG. 38A, the filament simulating terminals 1661 and 1662 of the filament-simulating circuit 1760 are respectively coupled to the pins 501 and 502 and the pins 503 and 504. When the lamp driving circuit outputs the detection signal for detecting the state of the filament, the detection signal passes the capacitors 1763 and 1764 and the resistors 1765 and 1766 so that the lamp driving circuit determines that the filaments of the LED lamp are normal.

In some embodiments, capacitance values of the capacitors 1763 and 1764 are low and so a capacitive reactance of the serially connected capacitors 1763 and 1764 is far lower than an impedance of the serially connected resistors 1765 and 1766 due to the lamp driving circuit outputting the high-frequency AC signal to drive LED lamp. Therefore, the filament-simulating circuit 1760 consumes fairly low power when the LED lamp operates normally, and so it almost does not affect the luminous efficiency of the LED lamp. Moreover, if any one of the capacitor 1763 and the resistor 1765 is short circuited or is an open circuit, or if any one of the capacitor 1764 and the resistor 1766 is short circuited or is an open circuit, the detection signal still passes through the filament-simulating circuit 1760 between the filament simulating terminals 1661 and 1662. Therefore, the filament-simulating circuit 1760 still operates normally when any one of the capacitor 1763 and the resistor 1765 is short circuited or is an open circuit or any one of the capacitor 1764 and the resistor 1766 is short circuited or is an open circuit, and so it has quite high fault tolerance.

In some embodiments, the current flow through the filament-simulating circuit is lower than 1 ampere. The capacitor may be chosen from a ceramic capacitor or a metallic polypropylene film capacitor, such as: Class 2 ceramic capacitor, X2 metallic polypropylene film capacitor. When the Class 2 ceramic capacitor is chosen, the capacitance is lower than 100 nF and the internal resistance is lower. Therefore, the current flowing through the filament-simulating circuit 1760 could be reduced to a range from about 10 to about 100 mA and power consumption and heat are reduced such that the temperature may be lower than 70° C. In some embodiments, the temperature may be in a range from about 50 to 60° C.

When a flexible board(s) is used, the LEDs and the active and passive components of the power supply module may be totally or partially deposited on the same flexible board or different flexible boards for simplifying the structure of the LED tube lamp. In certain embodiments, the capacitor is the X7R multi-layer ceramic chip capacitor, with the capacitance being more than 100 nF and the current flowing through the filament-simulating circuit 1760 ranging from about 100 to about 1000 mA.

FIG. 39A is a block diagram of a power supply module in an LED tube lamp according to an exemplary embodiment. Compared to that shown in FIG. 29D, the present embodiment comprises the rectifying circuits 510 and 540, the filtering circuit 520, and the LED lighting module 530, and further comprises an over voltage protection (OVP) circuit 1570. The OVP circuit 1570 is coupled to the filtering output terminals 521 and 522 for detecting the filtered signal. The OVP circuit 1570 clamps the level of the filtered signal when determining the level thereof higher than a defined OVP value. Hence, the OVP circuit 1570 protects the LED lighting module 530 from damage due to an OVP condition.

FIG. 39B is a schematic diagram of an overvoltage protection (OVP) circuit according to an exemplary embodiment. The OVP circuit 1670 comprises a voltage clamping diode 1671, such as zener diode, coupled to the filtering output terminals 521 and 522. The voltage clamping diode 1671 is conducted to clamp a voltage difference at a breakdown voltage when the voltage difference of the filtering output terminals 521 and 522 (i.e., the level of the filtered signal) reaches the breakdown voltage. The over voltage protection circuit 1670 could protect the LED driving module 530 from damage due to transient high voltage, such as: the instant-start ballast may generate high-voltage AC voltage for igniting the florescent lamp during the starting period. A defined protection voltage of the over voltage protection circuit 1670 (or the breakdown voltage of the voltage clamping diode 1671) may be lower than 500 volts, such as, for example, ranging from about 100 to about 500 volts. In some embodiments, the defined protection voltage of the over voltage protection circuit 1670 may be lower than 400 volts, such as, for example, ranging from about 300 to about 400 volts.

FIG. 39C is a schematic diagram of an overvoltage protection (OVP) circuit according to an exemplary embodiment. Referring to FIG. 39C, the over voltage protection circuit 1770 comprises a symmetrical trigger diode 1771, resistors 1772, 1774 and 1776, a capacitor 1733 and a switch 1775. The symmetrical trigger diode 1771, the resistor 1772 and the capacitor 1733 are connected in series between a first filtering output terminal 521 and a second filtering output terminal 522. One end of the symmetrical trigger diode 1771 is coupled to the first filtering output terminal 521, one end of the capacitor 1773 is coupled to the second filtering output terminal 522, and the resistor 1772 is coupled between the symmetrical trigger diode 1771 and the capacitor 1773. The resistor 1774 and the switch 1775 are connected in series between the first filtering output terminal 521 and the second filtering output terminal 522. One end of the resistor 1774 is coupled to the first filtering output terminal 521, the other end is coupled to the switch 1775. One end of the switch 1775 is coupled to the second filtering output terminal 522, and one control end is coupled to a connection node of the resistor 1772 and the capacitor 1773 through the resistor 1776. When a voltage difference of the first filtering output terminal 521 and the second filtering output terminal 522 (i.e., the voltage level of the filtered signal) reaches or is higher than the breakover voltage of the symmetrical trigger diode 1771, the symmetrical trigger diode 1771 is conducted, and so a voltage of the capacitor 1773 is raised to trigger the switch 1775 to be conducted to protect the LED driving module 530.

In some embodiments, the breakover voltage of the symmetrical trigger diode 1771 ranges from about 400 to about 1300 volts. In certain embodiments, the breakover voltage of the symmetrical trigger diode 1771 may range from about 450 to about 700 volts. In still other embodiments, the breakover voltage of the symmetrical trigger diode 1771 ranges from about 500 to about 600 volts.

Referring to FIG. 40A, a block diagram of an LED tube lamp including a power supply module in accordance with certain embodiments is illustrated. Compared to the LED lamp shown in FIG. 24B, the LED tube lamp of FIG. 40A comprises two rectifying circuits 510 and 540, a filtering circuit 520, and an LED lighting module 530, and further comprises an installation detection module 2520. The installation detection module 2520 is coupled to the rectifying circuit 510 (and/or the rectifying circuit 540) via an installation detection terminal 2521 and is coupled to the filtering circuit 520 via an installation detection terminal 2522. The installation detection module 2520 detects the signal passing through the installation detection terminals 2521 and 2522 and determines whether to cut off an external driving signal passing through the LED tube lamp based on the detected result. The installation detection module includes circuitry configured to perform these steps, and thus may be referred to as an installation detection circuit, or more generally as a detection circuit or cut-off circuit. When an LED tube lamp is not yet installed on a lamp socket or holder, or in some cases if it is not installed properly or is only partly installed (e.g., one side is connected to a lamp socket, but not the other side yet), the installation detection module 2520 detects a smaller current and determines the signal is passing through a high impedance. In this case, in certain embodiments, the installation detection circuit 2520 is in a cut-off state to make the LED tube lamp stop working. Otherwise, the installation detection module 2520 determines that the LED tube lamp has already been installed on the lamp socket or holder, and it keeps on conducting to make the LED tube lamp working normally.

For example, in some embodiments, when a current passing through the installation detection terminals is greater than or equal to a specific, defined installation current (or a current value), which may indicate that the current supplied to the lighting module 530 is greater than or equal to a specific, defined operating current, the installation detection module is conductive to make the LED tube lamp operate in a conductive state. For example, a current greater than or equal to the specific current value may indicate that the LED tube lamp has correctly been installed in the lamp socket or holder. When the current passing through the installation detection terminals is smaller than the specific, defined installation current (or the current value), which may indicate that the current supplied to the lighting module 530 is less than a specific, defined operating current, the installation detection module cuts off current to make the LED tube lamp enter in a non-conducting state based on determining that the LED tube lamp has been not installed in, or does not properly connect to, the lamp socket or holder. In certain embodiments, the installation detection module 2520 determines conducting or cutting off based on the impedance detection to make the LED tube lamp operate in a conducting state or enter non-conducting state. The LED tube lamp operating in a conducting state may refer to the LED tube lamp including a sufficient current passing through the LED module to cause the LED light sources to emit light. The LED tube lamp operating in a cut-off state may refer to the LED tube lamp including an insufficient current or no current passing through the LED module so that the LED light sources do not emit light. Accordingly, the occurrence of electric shock caused by touching the conductive part of the LED tube lamp which is incorrectly installed on the lamp socket or holder can be better avoided.

Referring to FIG. 40B, a block diagram of an installation detection module in accordance with certain embodiments is illustrated. The installation detection module includes a switch circuit 2580, a detection pulse generating module 2540, a detection result latching circuit 2560, and a detection determining circuit 2570. Certain of these circuits may be referred to as first, second, third, etc., circuits as a naming convention to differentiate them from each other.

The detection determining circuit 2570 is coupled to and detects the signal between the installation detection terminals 2521 (through a switch circuit coupling terminal 2581 and the switch circuit 2580) and 2522. It is also coupled to the detection result latching circuit 2560 via a detection result terminal 2571 to transmit the detection result signal. The detection determining circuit 2570 may be configured to detect a current passing through terminals 2521 and 2522 (e.g., to detect whether the current is above or below a specific value).

The detection pulse generating module 2540 is coupled to the detection result latching circuit 2560 via a pulse signal output terminal 2541, and generates a pulse signal to inform the detection result latching circuit 2560 of a time point for latching (storing) the detection result. For example, the detection pulse generating module 2540 may be a circuit configured to generate a signal that causes a latching circuit, such as the detection result latching circuit 2560 to enter and remain in a state that corresponds to one of a conducting state or a cut-off state for the LED tube lamp. The detection result latching circuit 2560 stores the detection result according to the detection result signal (or detection result signal and pulse signal), and transmits or provides the detection result to the switch circuit 2580 coupled to the detection result latching circuit 2560 via a detection result latching terminal 2561. The switch circuit 2580 controls the state between conducting or cut off between the installation detection terminals 2521 and 2522 according to the detection result.

Referring to FIG. 40C, a block diagram of a detection pulse generating module in accordance with certain embodiments is illustrated. A detection pulse generating module 2640 may be a circuit that includes multiple capacitors 2642, 2645, and 2646, multiple resistors 2643, 2647, and 2648, two buffers 2644, and 2651, an inverter 2650, a diode 2649, and an OR gate 2652. With use or operation, the capacitor 2642 and the resistor 2643 connect in series between a driving voltage (e.g., a driving voltage source, which may be a node of a power supply), such as VCC usually defined as a high logic level voltage, and a reference voltage (or potential), such as ground potential in this embodiment. The connection node between the capacitor 2642 and the resistor 2643 is coupled to an input terminal of the buffer 2644. The resistor 2647 is coupled between the driving voltage, e.g., VCC, and an input terminal of the inverter 2650. The resistor 2648 is coupled between an input terminal of the buffer 2651 and the reference voltage, e.g. ground potential in this embodiment. An anode of the diode 2649 is grounded and a cathode thereof is coupled to the input terminal of the buffer 2651. First ends of the capacitors 2645 and 2646 are jointly coupled to an output terminal of the buffer 2644, and second, opposite ends of the capacitors 2645 and 2646 are respectively coupled to the input terminal of the inverter 2650 and the input terminal of the buffer 2651. An output terminal of the inverter 2650 and an output terminal of the buffer 2651 are coupled to two input terminals of the OR gate 2652. The voltage (or potential) for “high logic level” and “low logic level,” as discussed in this specification, may be relative to another voltage (or potential) or a certain reference voltage (or potential) in circuits, and further may be described as “logic high logic level” and “logic low logic level.”

When an end cap of an LED tube lamp is inserted into a lamp socket and the other end cap thereof is electrically coupled to a human body, or when both end caps of the LED tube lamp are inserted into the lamp socket, the LED tube lamp is conductive with electricity. At this moment, the installation detection module enters a detection stage. The voltage on the connection node of the capacitor 2642 and the resistor 2643 is high initially (equals to the driving voltage, VCC) and decreases with time to zero finally. The input terminal of the buffer 2644 is coupled to the connection node of the capacitor 2642 and the resistor 2643, so the buffer 2644 outputs a high logic level signal at the beginning and changes to output a low logic level signal when the voltage on the connection node of the capacitor 2642 and the resistor 2643 decreases to a low logic trigger logic level. As a result, the buffer 2644 is configured to produce an input pulse signal and then remain in a low logic level thereafter (stops outputting the input pulse signal.) The width for the input pulse signal may be described as equal to one (initial setting) time period, which is determined by the capacitance value of the capacitor 2642 and the resistance value of the resistor 2643.

Next, the operations for the buffer 2644 to produce the pulse signal with the initial setting time period will be described below. Since the voltage on a first end of the capacitor 2645 and on a first end of the resistor 2647 is equal to the driving voltage VCC, the voltage on the connection node of both of them is also a high logic level. The first end of the resistor 2648 is grounded and the first end of the capacitor 2646 receives the pulse signal from the buffer 2644, so the connection node of the capacitor 2646 and the resistor 2648 has a high logic level voltage at the beginning but this voltage decreases with time to zero (in the meantime, the capacitor stores the voltage being equal to or approaching the driving voltage VCC.) Accordingly, initially the inverter 2650 outputs a low logic level signal and the buffer 2651 outputs a high logic level signal, and hence the OR gate 2652 outputs a high logic level signal (a first pulse signal) at the pulse signal output terminal 2541. At this moment, the detection result latching circuit 2560 stores the detection result for the first time according to the detection result signal and the pulse signal. During that initial pulse time period, detection pulse generating module 2540 outputs a high logic level signal, which results in the detection result latching circuit 2560 storing the result of that high logic level signal.

When the voltage on the connection node of the capacitor 2646 and the resistor 2648 decreases to the low logic trigger logic level, the buffer 2651 changes to output a low logic level signal to make the OR gate 2652 output a low logic level signal at the pulse signal output terminal 2541 (stops outputting the first pulse signal.) The width of the first pulse signal output from the OR gate 2541 is in part determined by the capacitance value of the capacitor 2646 and the resistance value of the resistor 2648.

The operation after the buffer 2644 stops outputting the pulse signal is described as below. For example, the operation may be initially in an operating stage. Since the capacitor 2646 stores the voltage being almost equal to the driving voltage VCC, and when the buffer 2644 instantaneously changes its output from a high logic level signal to a low logic level signal, the voltage on the connection node of the capacitor 2646 and the resistor 2648 is below zero but will be pulled up to zero by the diode 2649 rapidly charging the capacitor. Therefore, the buffer 2651 still outputs a low logic level signal.

On the other hand, when the buffer 2644 instantaneously changes its output from a high logic level signal to a low logic level signal, the voltage on the one end of the capacitor 2645 also changes from the driving voltage VCC to zero instantly. This makes the connection node of the capacitor 2645 and the resistor 2647 have a low logic level signal. At this moment, the output of the inverter 2650 changes to a high logic level signal to make the OR gate output a high logic level signal (a second pulse signal.) The detection result latching circuit 2560 stores the detection result for a second time according to the detection result signal and the pulse signal. Next, the driving voltage VCC charges the capacitor 2645 through the resistor 2647 to make the voltage on the connection node of the capacitor 2645 and the resistor 2647 increase with time to the driving voltage VCC. When the voltage on the connection node of the capacitor 2645 and the resistor 2647 increases to reach a high logic trigger logic level, the inverter 2650 outputs a low logic level signal again to make the OR gate 2652 stop outputting the second pulse signal. The width of the second pulse signal is determined by the capacitance value of the capacitor 2645 and the resistance value of the resistor 2647.

As those mentioned above, in certain embodiments, the detection pulse generating module 2640 generates two high logic level pulse signals in the detection stage, which are the first pulse signal and the second pulse signal. These pulse signals are output from the pulse signal output terminal 2541. Moreover, there is an interval with a defined time between the first and second pulse signals (e.g., an opposite-logic signal, which may have a low logic level when the pulse signals have a high logic level), and the defined time is determined by the capacitance value of the capacitor 2642 and the resistance value of the resistor 2643 (and may also depend on the capacitance values of capacitors 2645 and 2646 and resistance values of resistors 2647 and 2648).

From the detection stage entering the operating stage (e.g., assuming the LED tube lamp is properly connected to draw a normal current), the detection pulse generating module 2640 does not produce the pulse signal any more, and keeps the pulse signal output terminal 2541 on a low logic level potential.

Referring to FIG. 40D, a detection determining circuit in accordance with certain embodiments is illustrated. An exemplary detection determining circuit 2670 includes a comparator 2671, and a resistor 2672. A negative input terminal of the comparator 2671 receives a reference logic level signal (or a reference voltage) Vref, a positive input terminal thereof is grounded through the resistor 2672 and is also coupled to a switch circuit coupling terminal 2581. Referring to FIG. 40B and FIG. 40D, the signal flowing into the switch circuit 2580 from the installation detection terminal 2521 outputs to the switch circuit coupling terminal 2581 to the resistor 2672. When the current of the signal passing through the resistor 2672 reaches a certain level (for example, bigger than or equal to a defined current for installation, (e.g. 2A) and this makes the voltage on the resistor 2672 higher than the reference voltage Vref (referring to two end caps inserted into the lamp socket,) the comparator 2671 produces a high logic level detection result signal and outputs it to the detection result terminal 2571. For example, when an LED tube lamp is correctly installed on a lamp socket, the comparator 2671 outputs a high logic level detection result signal at the detection result terminal 2571, whereas the comparator 2671 generates a low logic level detection result signal and outputs it to the detection result terminal 2571 when a current passing through the resistor 2672 is insufficient to make the voltage on the resistor 2672 higher than the reference voltage Vref (referring to only one end cap inserted into the lamp socket.) Therefore, in some embodiments, when the LED tube lamp is incorrectly installed on the lamp socket or one end cap thereof is inserted into the lamp socket but the other one is grounded by an object such as a human body, the current will be too small to make the comparator 2671 output a high logic level detection result signal to the detection result terminal 2571.

Referring to FIG. 40E, a schematic detection result latching circuit according to some exemplary embodiments is illustrated. A detection result latching circuit 2660 includes a D flip-flop 2661, a resistor 2662, and an OR gate 2663. The D flip-flop 2661 has a CLK input terminal coupled to a detection result terminal 2571, and a D input terminal coupled to a driving voltage VCC. When the detection result terminal 2571 first outputs a low logic level detection result signal, the D flip-flop 2661 initially outputs a low logic level signal at a Q output terminal thereof, but the D flip-flop 2661 outputs a high logic level signal at the Q output terminal thereof when the detection result terminal 2571 outputs a high logic level detection result signal. The resistor 2662 is coupled between the Q output terminal of the D flip-flop 2661 and a reference voltage, such as ground potential. When the OR gate 2663 receives the first or second pulse signals from the pulse signal output terminal 2541 or receives a high logic level signal from the Q output terminal of the D flip-flop 2661, the OR gate 2663 outputs a high logic level detection result latching signal at a detection result latching terminal 2561. The detection pulse generating module 2640 only in the detection stage outputs the first and the second pulse signals to make the OR gate 2663 output the high logic level detection result latching signal, and thus the D flip-flop 2661 decides the detection result latching signal to be the high logic level or the low logic level the rest of the time, e.g. including the operating stage after the detection stage. Accordingly, when the detection result terminal 2571 has no high logic level detection result signal, the D flip-flop 2661 keeps a low logic level signal at the Q output terminal to make the detection result latching terminal 2561 also keep a low logic level detection result latching signal in the detection stage. On the contrary, once the detection result terminal 2571 has a high logic level detection result signal, the D flip-flop 2661 outputs and keeps a high logic level signal (e.g., based on VCC) at the Q output terminal. In this way, the detection result latching terminal 2561 keeps a high logic level detection result latching signal in the operating stage as well.

Referring to FIG. 40F, a schematic switch circuit according to some embodiments is illustrated. A switch circuit 2680 includes a transistor, such as a bipolar junction transistor (BJT) 2681, as being a power transistor, which has the ability of dealing with high current/power and is suitable for the switch circuit. The BJT 2681 has a collector coupled to an installation detection terminal 2521, a base coupled to a detection result latching terminal 2561, and an emitter coupled to a switch circuit coupling terminal 2581. When the detection pulse generating module 2640 produces the first and second pulse signals, the BJT 2681 is in a transient conduction state. This allows the detection determining circuit 2670 to perform the detection for determining the detection result latching signal to be a high logic level or a low logic level. When the detection result latching circuit 2660 outputs a high logic level detection result latching signal at the detection result latching terminal 2561, the BJT 2681 is in the conducting state to make the installation detection terminals 2521 and 2522 conducting. In contrast, when the detection result latching circuit 2660 outputs a low logic level detection result latching signal at the detection result latching terminal 2561 and the output from detection pulse generating module 2640 is a low logic level, the BJT 2681 is cut-off or in the blocking state to make the installation detection terminals 2521 and 2522 cut-off or blocking.

Since the external driving signal is an AC signal and in order to avoid the detection error resulting from the logic level of the external driving signal being just around zero when the detection determining circuit 2670 detects, the detection pulse generating module 2640 generates the first and second pulse signals to let the detection determining circuit 2670 performing two detections. So the issue of the logic level of the external driving signal being just around zero in a single detection can be avoided. In some cases, the time difference between the productions of the first and second pulse signals is not multiple times of half one cycle of the external driving signal. For example, it does not correspond to the multiple phase differences in 180 degrees of the external driving signal. In this way, when one of the first and second pulse signals is generated and unfortunately the external driving signal is around zero, it can be avoided that the external driving signal is also around zero as another being generated.

The time difference between the productions of the first and second pulse signals, for example, an interval with a defined time between both of them can be represented as following: the interval=(X+Y)(T/2), where T represents the cycle of an external driving signal, X is a natural number, 0<Y<1, with Y in some embodiments in the range of 0.05-0.95, and in some embodiments in the range of 0.15-0.85.

Furthermore, in order to avoid the installation detection module entering the detection stage from misjudgment resulting from the logic level of the driving voltage VCC being too small, the first pulse signal can be set to be produced when the driving voltage VCC reaches or is higher than a defined logic level. For example, in some embodiments, the detection determining circuit 2670 works after the driving voltage VCC reaching a high enough logic level in order to prevent the installation detection module from misjudgment due to an insufficient logic level.

According to the examples mentioned above, when one end cap of an LED tube lamp is inserted into a lamp socket and the other one floats or electrically couples to a human body or other grounded object, the detection determining circuit outputs a low logic level detection result signal because of high impedance. The detection result latching circuit stores the low logic level detection result signal based on the pulse signal of the detection pulse generating module, making it as the low logic level detection result latching signal, and keeps the detection result in the operating stage, without changing the logic value. In this way, the switch circuit keeps cutting-off or blocking instead of conducting continually. And further, the electric shock situation can be prevented and the requirement of safety standard can also be met. On the other hand, when two end caps of the LED tube lamp are correctly inserted into the lamp socket, the detection determining circuit outputs a high logic level detection result signal because the impedance of the circuit for the LED tube lamp itself is small. The detection result latching circuit stores the high logic level detection result signal based on the pulse signal of the detection pulse generating module, making it as the high logic level detection result latching signal, and keeps the detection result in the operating stage. So the switch circuit keeps conducting to make the LED tube lamp work normally in the operating stage.

In some embodiments, when one end cap of the LED tube lamp is inserted into the lamp socket and the other one floats or electrically couples to a human body, the detection determining circuit outputs a low logic level detection result signal to the detection result latching circuit, and then the detection pulse generating module outputs a low logic level signal to the detection result latching circuit to make the detection result latching circuit output a low logic level detection result latching signal to make the switch circuit cutting-off or blocking. As such, the switch circuit blocking makes the installation detection terminals, e.g. the first and second installation detection terminals, blocking. As a result, the LED tube lamp is in non-conducting or blocking state.

However, in some embodiments, when two end caps of the LED tube lamp are correctly inserted into the lamp socket, the detection determining circuit outputs a high logic level detection result signal to the detection result latching circuit to make the detection result latching circuit output a high logic level detection result latching signal to make the switch circuit conducting. As such, the switch circuit conducting makes the installation detection terminals, e.g. the first and second installation detection terminals, conducting. As a result, the LED tube lamp operates in conducting state.

According to certain embodiments, the width of the pulse signal generated by the detection pulse generating module is between 10 μs to 1 ms, and it is used to make the switch circuit conducting for a short period when the LED tube lamp conducts instantaneously. In some embodiments, a pulse current is generated to pass through the detection determining circuit for detecting and determining. Since the pulse is for a short time and not for a long time, the electric shock situation will not occur. Furthermore, the detection result latching circuit also keeps the detection result during the operating stage, and no longer changes the detection result stored previously complying with the circuit state changing. Consequences resulting from changing the detection result can thus be avoided. In some embodiments, the installation detection module, such as the switch circuit, the detection pulse generating module, the detection result latching circuit, and the detection determining circuit, could be integrated into a chip and then embedded in circuits for saving the circuit cost and layout space.

Referring to FIG. 37, in one embodiment, each of the LED light sources 202 may be provided with an LED lead frame 202 b having a recess 202 a, and an LED chip 18 may be disposed in the recess 202 a. The recess 202 a may be one or more than one in amount. The recess 202 a may be filled with phosphor covering the LED chip 18 to convert emitted light therefrom into a desired light color. Compared with a conventional LED chip being a substantial square, the LED chip 18 in this embodiment may be rectangular with the dimension of the length side to the width side at a ratio that ranges from about 2:1 to about 10:1. In some embodiments, the ratio may range from about 2.5:1 to about 5:1. In certain embodiments, the ration may range from about 3:1 to about 4.5:1. Moreover, the LED chip 18 is in some embodiments arranged with its length direction extending along the length direction of the lamp tube 1 to increase the average current density of the LED chip 18 and improve the overall illumination field shape of the lamp tube 1. The lamp tube 1 may have a number of LED light sources 202 arranged into one or more rows, and each row of the LED light sources 202 is arranged along the length direction (Y-direction) of the lamp tube 1.

Referring again to FIG. 37, the recess 202 a is enclosed by two parallel first sidewalls 15 and two parallel second sidewalls 16 with the first sidewalls 15 being lower than the second sidewalls 16. The two first sidewalls 15 are arranged to be located along a length direction (Y-direction) of the lamp tube 1 and extend along the width direction (X-direction) of the lamp tube 1, and two second sidewalls 16 are arranged to be located along a width direction (X-direction) of the lamp tube 1 and extend along the length direction (Y-direction) of the lamp tube 1. The extending direction of the first sidewalls 15 may be substantially rather than exactly parallel to the width direction (X-direction) of the lamp tube 1, and the first sidewalls may have various outlines such as zigzag, curved, wavy, and the like. Similarly, the extending direction of the second sidewalls 16 may be substantially rather than exactly parallel to the length direction (Y-direction) of the lamp tube 1, and the second sidewalls may have various outlines such as zigzag, curved, wavy, and the like. In one row of the LED light sources 202, the arrangement of the first sidewalls 15 and the second sidewalls 16 for each LED light source 202 can be same or different.

Having the first sidewalls 15 being lower than the second sidewalls 16 and proper distance arrangement, the LED lead frame 202 b allows dispersion of the light illumination to cross over the LED lead frame 202 b without causing uncomfortable visual feeling to people observing the LED tube lamp along the Y-direction. In some embodiments, the first sidewalls 15 may not be lower than the second sidewalls, however, and in this case the rows of the LED light sources 202 are more closely arranged to reduce grainy effects. On the other hand, when a user of the LED tube lamp observes the lamp tube thereof along the X-direction, the second sidewalls 16 also can block user's line of sight from seeing the LED light sources 202, and which reduces unpleasing grainy effects.

Referring again to FIG. 37, the first sidewalls 15 each includes an inner surface 15 a facing toward outside of the recess 202 a. The inner surface 15 a may be designed to be an inclined plane such that the light illumination easily crosses over the first sidewalls 15 and spreads out. The inclined plane of the inner surface 15 a may be flat or cambered or combined shape. In some embodiments, when the inclined plane is flat, the slope of the inner surface 15 a ranges from about 30 degrees to about 60 degrees. Thus, an included angle between the bottom surface of the recess 202 a and the inner surface 15 a may range from about 120 to about 150 degrees. In some embodiments, the slope of the inner surface 15 a ranges from about 15 degrees to about 75 degrees, and the included angle between the bottom surface of the recess 202 a and the inner surface 15 a ranges from about 105 degrees to about 165 degrees.

There may be one row or several rows of the LED light sources 202 arranged in a length direction (Y-direction) of the lamp tube 1. In the case of one row, in one embodiment, the second sidewalls 16 of the LED lead frames 202 b of all of the LED light sources 202 located in the same row are disposed in same straight lines to respectively form two walls for blocking the user's line of sight seeing the LED light sources 202. In the case of several rows, in some embodiments, only the LED lead frames 202 b of the LED light sources 202 disposed in the outermost two rows are disposed in same straight lines to respectively form walls for blocking user's line of sight seeing the LED light sources 202. In the case of several rows, it may be that the LED lead frames 202 b of the LED light sources 202 disposed in the outermost two rows are disposed in same straight lines to respectively from walls for blocking user's line of sight seeing the LED light sources 202. The LED lead frames 202 b of the LED light sources 202 disposed in the other rows can have different arrangements. For example, as far as the LED light sources 202 located in the middle row (third row) are concerned, the LED lead frames 202 b thereof may be arranged such that: each LED lead frame 202 b has the first sidewalls 15 arranged along the length direction (Y-direction) of the lamp tube 1 with the second sidewalls 16 arranged along in the width direction (X-direction) of the lamp tube 1; each LED lead frame 202 b has the first sidewalls 15 arranged along the width direction (X-direction) of the lamp tube 1 with the second sidewalls 16 arranged along the length direction (Y-direction) of the lamp tube 1; or the LED lead frames 202 b are arranged in a staggered manner. To reduce grainy effects caused by the LED light sources 202 when a user of the LED tube lamp observes the lamp tube thereof along the X-direction, it may be enough to have the second sidewalls 16 of the LED lead frames 202 b of the LED light sources 202 located in the outmost rows to block user's line of sight from seeing the LED light sources 202. Different arrangements may be used for the second sidewalls 16 of the LED lead frames 202 b of one or several of the LED light sources 202 located in the outmost two rows.

In summary, when a plurality of the LED light sources 202 are arranged in a row extending along the length direction of the lamp tube 1, the second sidewalls 16 of the LED lead frames 202 b of all of the LED light sources 202 located in the same row may be disposed in same straight lines to respectively form walls for blocking user's line of sight seeing the LED light sources 202. When a plurality of the LED light sources 202 are arranged in a number of rows being located along the width direction of the lamp tube 1 and extending along the length direction of the lamp tube 1, the second sidewalls 16 of the LED lead frames 202 b of all of the LED light sources 202 located in the outmost two rows may be disposed in straight lines to respectively form two walls for blocking user's line of sight seeing the LED light sources 202. The one or more than one rows located between the outmost rows may have the first sidewalls 15 and the second sidewalls 16 arranged in a way the same as or different from that for the outmost rows.

The LED tube lamps according to various different exemplary embodiments are described as above. With respect to an entire LED tube lamp, the features including “having the structure-strengthened end region”, “adopting the bendable circuit sheet as the LED light strip”, “coating the adhesive film on the inner surface of the lamp tube”, “coating the diffusion film on the inner surface of the lamp tube”, “covering the diffusion film in form of a sheet above the LED light sources”, “coating the reflective film on the inner surface of the lamp tube”, “the end cap including the thermal conductive member”, “the end cap including the magnetic metal member”, “the LED light source being provided with the lead frame”, and “utilizing the circuit board assembly to connect the LED light strip and the power supply” may be applied in practice singly or integrally such that only one of the features is practiced or a number of the features are simultaneously practiced.

Furthermore, any of the features “having the structure-strengthened end region”, “adopting the bendable circuit sheet as the LED light strip”, “coating the adhesive film on the inner surface of the lamp tube”, “coating the diffusion film on the inner surface of the lamp tube”, “covering the diffusion film in form of a sheet above the LED light sources”, “coating the reflective film on the inner surface of the lamp tube”, “the end cap including the thermal conductive member”, “the end cap including the magnetic metal member”, “the LED light source being provided with the lead frame”, “utilizing the circuit board assembly (including a long circuit sheet and a short circuit board) to connect the LED light strip and the power supply”, “a rectifying circuit”, “a filtering circuit”, “a driving circuit”, “an anti-flickering circuit”, “a protection circuit”, “a mode switching circuit”, “an overvoltage protection circuit”, “a ballast detection circuit”, “a ballast-compatible circuit”, and “a filament-simulating circuit” may include, but are not necessarily limited to any related technical points and their variations and any combination thereof as described in the above-mentioned embodiments.

As an example, the feature “having the structure-strengthened end region” may include, but are not limited to, “the lamp tube includes a main body region, a plurality of rear end regions, and a transition region connecting the main body region and the rear end regions, wherein the two ends of the transition region are arc-shaped in a cross-section view along the axial direction of the lamp tube; the rear end regions are respectively sleeved with end caps; the outer diameter of at least one of the rear end regions is less than the outer diameter of the main body region; the end caps have same outer diameters as that of the main body region.”

As an example, the feature “adopting the bendable circuit sheet as the LED light strip” may include, but is not limited to, “the connection between the bendable circuit sheet and the power supply is by way of wire bonding or soldering bonding; the bendable circuit sheet includes a wiring layer and a dielectric layer arranged in a stacked manner; the bendable circuit sheet has a circuit protective layer made of ink to reflect lights and has widened part along the circumferential direction of the lamp tube to function as a reflective film.”

As an example, the feature “coating the diffusion film on the inner surface of the lamp tube” may include, but is not limited to, “the composition of the diffusion film includes calcium carbonate, halogen calcium phosphate and aluminum oxide, or any combination thereof, and may further include thickener and a ceramic activated carbon; the diffusion film may be a sheet covering the LED light source.”

As an example, the feature “coating the reflective film on the inner surface of the lamp tube” may include, but is not limited to “the LED light sources are disposed above the reflective film, within an opening in the reflective film or beside the reflective film.”

As an example, the feature in which the end cap includes the thermal conductive member may include, but is not limited to, the features in which the end cap includes an electrically insulating tube, and the hot melt adhesive is partially or completely filled in the accommodation space between the inner surface of the thermal conductive member and the outer surface of the lamp tube. The feature in which the end cap including the magnetic metal member may include, but is not limited to the features in which the magnetic metal member is circular or non-circular, has openings or indentation/embossment to reduce the contact area between the inner peripheral surface of the electrically insulating tube and the outer surface of the magnetic metal member, and/or has supporting portions and protruding portions to support the magnetic metal member or reduce the contact area between the electrically insulating tube and the magnetic metal member.

As an example, the feature in which the LED light source is provided with the lead frame may include, but is not limited to, the features in which the lead frame has a recess for receive an LED chip, and/or the recess is enclosed by first sidewalls and second sidewalls with the first sidewalls being lower than the second sidewalls, wherein the first sidewalls are arranged to locate along a length direction of the lamp tube while the second sidewalls are arranged to locate along a width direction of the lamp tube.

As an example, the feature in which utilizing the circuit board assembly to connect the LED light strip and the power supply may include, but is not limited to, the features in which the circuit board assembly has a long circuit sheet and a short circuit board that are adhered to each other with the short circuit board being adjacent to the side edge of the long circuit sheet, the short circuit board is provided with a power supply module to form the power supply, and/or the short circuit board is stiffer than the long circuit sheet.”

The above-mentioned features of the present disclosure can be accomplished in any combination to improve the LED tube lamp, and the above embodiments are described by way of example only. The present disclosure is not herein limited, and many variations are possible without departing from the spirit of the present disclosure and the scope as defined in the appended claims. 

What is claimed is:
 1. An LED tube lamp, comprising: a first rectifying circuit, coupled to a first pin and a second pin and configured to rectify an external driving signal transmitted from the first pin and/or the second pin; a second rectifying circuit coupled to a third pin and a fourth pin and configured to rectify the external driving signal with the first rectifying circuit; a filter circuit, coupled to the first rectifying circuit and configured to filter the rectified signal; an LED lighting module, having a driving circuit and an LED module, and coupled to the filter circuit and connected to receive the filtered signal; a mode determination circuit, configured to generate a first determined result signal based on the external driving signal; and a mode switching circuit, coupled to the filter circuit and the driving circuit, configured to determine whether to perform a first driving mode or a second driving mode based on the first determined result signal, wherein the driving circuit is configured to receive a filtered signal from the filtering circuit and drive the LED module to emit light when performing the first driving mode, and the filtered signal bypasses at least a component of the driving circuit to drive the LED module to emit light when performing the second driving mode.
 2. The LED tube lamp according to claim 1, wherein the mode determination circuit comprises a voltage determination circuit and is configured to generate the first determined result signal when the external driving signal is higher than a defined voltage value.
 3. The LED tube lamp according to claim 2, wherein the voltage determination circuit comprises a symmetrical trigger diode.
 4. The LED tube lamp according to claim 3, wherein the symmetrical trigger diode is coupled between two filtering output terminals of the filter circuit and generates the first determined result signal when the level of the filtered signal is higher than a trigger voltage of the symmetrical trigger diode.
 5. The LED tube lamp according to claim 4, wherein the mode determination circuit further comprises a first resistor, a second resistor and a switch, the first resistor connected with the symmetrical trigger diode in series between the two filtering output terminals, the second resistor and the switch are connected in series between the two filtering output terminals, and a control of the switch is coupled to a connection node of the first resistor and the symmetrical trigger diode to generate a second determined result signal at a connection node of the second resistor and the switch.
 6. The LED tube lamp according to claim 5, wherein the mode switching circuit has a first mode switch and a second mode switch, the first mode switch is coupled to one of a diode or a conversion switch of the driving circuit and conducts a current from/to the diode or the conversion switch based on the first determined result signal when performing the first driving mode, and the second mode switch is coupled to the filter circuit and the LED module and conducts a current from the filter circuit based on the second determined result signal when performing the second driving mode.
 7. The LED tube lamp according to claim 1, wherein the mode determination circuit comprises a frequency determination circuit and generates the first determined result signal when a frequency of the external driving signal is higher than a defined frequency value.
 8. The LED tube lamp according to claim 7, wherein the frequency determination circuit comprises a first resistor and a capacitor connected in series.
 9. The LED tube lamp according to claim 8, wherein the frequency determination circuit is coupled between two rectified output terminals of the rectifying circuit and generates the first determined result signal when the frequency of the rectified signal is higher than the defined frequency value.
 10. The LED tube lamp according to claim 9, wherein the mode determination circuit further comprises a second resistor and a switch connected in series between two filtering output terminals of the filter circuit, and a control of the switch is coupled to a connection node of the first resistor and the capacitor to generate a second determined result signal at a connection node of the second resistor and the switch.
 11. The LED tube lamp according to claim 10, wherein the mode switching circuit has a first mode switch and a second mode switch, the first mode switch is coupled to one of a diode or a conversion switch of the driving circuit and conducts a current from/to the diode or the conversion switch based on the first determined result signal when performing the first driving mode, and the second mode switch is coupled to the filter circuit and the LED module and conducts a current from the filter circuit based on the second determined result signal when performing the second driving mode.
 12. The LED tube lamp according to claim 1, wherein the driving circuit includes a controller, a switching circuit, and an energy storage circuit coupled to the switching circuit, the controller is configured for determining when to turn the switching circuit on or off according to a detection signal, the mode determination circuit is coupled to the mode switching circuit and the driving circuit, and the mode determination circuit controls whether to turn on or off the mode switching circuit through the first determined result signal.
 13. The LED tube lamp according to claim 12, wherein when performing the first driving mode the mode switching circuit is switched such that current flows through the driving circuit allowing the controller to turn on the switching circuit to supply current to the LED module for emitting light.
 14. The LED tube lamp according to claim 12, wherein when performing the second driving mode the mode switching circuit is switched such that the driving circuit causes the controller to turn off the switching circuit.
 15. The LED tube lamp according to claim 12, wherein the first driving mode is performed when the external driving signal is a relatively low frequency or voltage signal, and the second driving mode is performed when the external driving signal is a relatively high frequency or voltage signal.
 16. The LED tube lamp according to claim 12, wherein the switching circuit comprises a MOSFET.
 17. The LED tube lamp according to claim 12, wherein the energy storage circuit comprises an inductor and a diode connected in series.
 18. The LED tube lamp according to claim 12, further comprising: a capacitive filter coupled between the driving circuit and the LED module, to stabilize a voltage on the LED module, wherein the capacitive filter is coupled to the energy storage circuit and the mode switching circuit. 